Carbon and Alloy Steels and Alloy Steel Filler Metals

Question 1

1

Q: What is the carbon content range for low carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 1

A: Low carbon steel contains between 0.05% and 0.30% carbon.

Question 2

2

Q: What are the common uses for low carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 2

A: Low carbon steel is used for tanks, agricultural equipment, general fabrication, and structural shapes. It is tough, ductile, and can withstand rough treatment.

Question 3

3

Q: What is mild steel, and how does it relate to low carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 3

A: Mild steel is a subset of low carbon steel with a carbon content range between 0.15% and 0.30%. It is widely used in structural shapes and bar stock.

Question 4

4

Q: What is the carbon content range for medium carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 4

A: Medium carbon steel contains between 0.30% and 0.45% carbon.

Question 5

5

Q: What are the common applications for medium carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 5

A: Medium carbon steel is used for components that require higher strength and wear resistance, such as axles, connecting rods, and earth-moving equipment.

Question 6

6

Q: What makes medium carbon steel more difficult to work with compared to low carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 6

A: Medium carbon steel is stronger and harder than low carbon steel but is also more difficult to machine, forge, and weld.

Question 7

7

Q: What are the typical uses for high carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 7

A: High carbon steel is used for crankshafts, scraper blades, springs, and tools requiring high hardness and strength.

Question 8

8

Q: What is the carbon content range for high carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 8

A: High carbon steel contains between 0.45% and 0.75% carbon.

Question 9

9

Q: How does very high carbon steel differ from high carbon steel?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 9

A: Very high carbon steel has a carbon content range of 0.75% to 1.50%. It is even harder and more brittle than high carbon steel and is used for tools such as chisels, knives, and cutting equipment.

Question 10

10

Q: What is one key characteristic of high carbon and very high carbon steels?

Objective 1: List the carbon content and the uses for low carbon steel, medium carbon steel, and high carbon steel

Answer 10

A: Both high carbon and very high carbon steels respond well to heat treatment, making them suitable for applications requiring high hardness.

Question 11

1

Q: How does carbon content affect the weldability of steel?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 11

A: Higher carbon content reduces the weldability of steel because it increases the hardness and brittleness of the heat-affected zone (HAZ), leading to a higher risk of cracking.

Question 12

2

Q: What is considered a low carbon content in steel, and how does it affect weldability?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 12

A: Low carbon steel contains less than 0.30% carbon, making it highly weldable with minimal risk of cracking or other weld-related issues.

Question 13

3

Q: What happens to steel with medium carbon content during welding?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 13

A: Medium carbon steel (0.30% to 0.45% carbon) becomes more susceptible to cracking during welding, especially in the heat-affected zone, due to increased hardness.

Question 14

4

Q: Why is preheating often required for welding high carbon steel?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 14

A: High carbon steel (above 0.45% carbon) is prone to cracking and hardness in the heat-affected zone. Preheating helps reduce thermal shock and prevent rapid cooling, which can cause brittleness and cracking.

Question 15

5

Q: What is the carbon equivalent, and how is it used in welding?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 15

A: The carbon equivalent (CE) is a formula used to estimate the combined effect of carbon and other alloying elements on steel’s weldability. A higher CE indicates a greater risk of cracking during welding.

Question 16

6

Q: What role does post-weld heat treatment (PWHT) play in welding steels with high carbon content?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 16

A: PWHT is often required for steels with high carbon content to relieve internal stresses, reduce hardness in the heat-affected zone, and prevent cracking after welding.

Question 17

7

Q: How does the carbon content of filler metals influence the weldability of steel?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 17

A: Filler metals with higher carbon content can increase the hardness of the weld metal, leading to reduced ductility and a greater risk of cracking. Matching filler metal with the base metal’s carbon content is crucial.

Question 18

8

Q: What precautions should be taken when welding medium and high carbon steels?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 18

A: Precautions include preheating the steel to reduce rapid cooling, using low hydrogen filler metals, and potentially applying post-weld heat treatment to reduce hardness and minimize the risk of cracking.

Question 19

9

Q: How does carbon content affect the selection of welding procedures?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 19

A: As the carbon content increases, more controlled welding procedures, such as preheating, controlled cooling, and post-weld heat treatment, are required to maintain weld integrity and prevent cracking.

Question 20

10

Q: Why is low carbon steel easier to weld than high carbon steel?

Objective 2: Identify the effect of carbon content on the weldability of steel

Answer 20

A: Low carbon steel has lower hardness and ductility, reducing the risk of cracking and distortion during welding. High carbon steel is harder and more brittle, making it more prone to issues in the heat-affected zone.

Question 21

1

Q: What is the effect of carbon on the properties of steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 21

A: Carbon increases the hardness and strength of steel but reduces its ductility and weldability. Higher carbon content also increases the risk of cracking in the heat-affected zone during welding.

Question 22

2

Q: How does manganese affect the properties of carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 22

A: Manganese improves the strength, toughness, and hardenability of steel. It also helps deoxidize the steel during production, preventing porosity and cracking during welding.

Question 23

3

Q: What is the role of silicon in carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 23

A: Silicon acts as a deoxidizer, helping to remove oxygen during the steelmaking process. It also improves the strength and hardness of the steel without significantly affecting its ductility.

Question 24

4

Q: What is the effect of sulfur in carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 24

A: Sulfur is generally considered an impurity in steel, causing brittleness and reducing the weldability. However, controlled amounts of sulfur can improve machinability, especially in free-machining steels.

Question 25

5

Q: How does phosphorus affect carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 25

A: Phosphorus increases the strength and corrosion resistance of steel but makes it more brittle. High phosphorus content can reduce toughness, especially at lower temperatures.

Question 26

6

Q: What is the effect of chromium in carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 26

A: Chromium improves hardness, strength, and corrosion resistance. It is often added to carbon steel to produce low alloy steels or stainless steel.

Question 27

7

Q: How does nickel influence the properties of carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 27

A: Nickel increases toughness, impact strength, and corrosion resistance, especially at low temperatures. It is often used in steels that need to perform in harsh environments.

Question 28

8

Q: What role does molybdenum play in carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 28

A: Molybdenum improves the strength and toughness of steel, particularly at high temperatures. It also increases resistance to wear and corrosion.

Question 29

9

Q: What is the effect of vanadium in carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 29

A: Vanadium increases the strength, toughness, and wear resistance of steel by refining the grain structure. It is commonly used in high-strength low-alloy steels.

Question 30

10

Q: How does copper affect the properties of carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 30

A: Copper improves corrosion resistance, especially in atmospheric conditions. It is often added to weathering steels used in outdoor structures.

Question 31

11

Q: What is the effect of nitrogen in carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 31

A: Nitrogen increases the strength of steel, but excessive amounts can reduce ductility and toughness, making the steel more brittle and harder to weld.

Question 32

12

Q: How does aluminum affect carbon steel?

Objective 3: Identify the effects of elements in the properties of carbon steel

Answer 32

A: Aluminum is used as a deoxidizer in steel production. It refines grain size, improving toughness and strength in the final product.

Question 33

1

Q: What are the major alloying elements commonly found in alloy steels?

Objective 4: Identify the major alloying elements in alloy steels

Answer 33

A: The major alloying elements in alloy steels include chromium, nickel, molybdenum, vanadium, manganese, silicon, and tungsten.

Question 34

2

Q: What is the effect of chromium as an alloying element in steel?

Objective 4: Identify the major alloying elements in alloy steels

Answer 34

A: Chromium increases hardness, wear resistance, and corrosion resistance. It is a key element in stainless steel and other corrosion-resistant alloys.

Question 35

3

Q: How does nickel affect the properties of alloy steel?

Objective 4: Identify the major alloying elements in alloy steels

Answer 35

A: Nickel improves toughness, impact strength, and resistance to corrosion, particularly in low-temperature environments. It is often used in steels for pipelines and other critical applications.

Question 36

4

Q: What is the role of molybdenum in alloy steels?

Objective 4: Identify the major alloying elements in alloy steels

Answer 36

A: Molybdenum enhances strength, hardness, and high-temperature performance, making it useful for high-strength low alloy steels and components that operate in high-temperature environments, such as power plants.

Question 37

5

Q: How does vanadium improve alloy steel properties?

Objective 4: Identify the major alloying elements in alloy steels

Answer 37

A: Vanadium increases strength, toughness, and wear resistance by refining the grain structure of the steel, making it commonly used in high-strength low-alloy steels.

Question 37

6

Q: What is the effect of manganese as an alloying element in steel?

Objective 4: Identify the major alloying elements in alloy steels

Answer 37

A: Manganese improves strength, toughness, and hardenability. It also acts as a deoxidizer, helping to remove oxygen from molten steel during production.

Question 38

7

Q: How does silicon affect the properties of alloy steels?

Objective 4: Identify the major alloying elements in alloy steels

Answer 38

A: Silicon acts as a deoxidizer during steel production, improving strength and hardness without significantly affecting ductility.

Question 39

8

Q: What is the role of tungsten in alloy steels?

Objective 4: Identify the major alloying elements in alloy steels

Answer 39

A: Tungsten increases hardness and high-temperature strength, making it useful for tool steels and high-speed cutting tools.

Question 40

9

Q: How does the addition of alloying elements affect the weldability of alloy steels?

Objective 4: Identify the major alloying elements in alloy steels

Answer 40

A: Alloying elements like carbon, chromium, and molybdenum can reduce the weldability of steel by increasing hardness and the risk of cracking. Preheating and post-weld heat treatment may be required.

Question 41

10

Q: What is the role of copper as an alloying element in steel?

Objective 4: Identify the major alloying elements in alloy steels

Answer 41

A: Copper improves the corrosion resistance of steel, especially in atmospheric conditions, making it useful in weathering steels.

Question 42

1

Q: What are low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 42

A: Low alloy steels are steels that contain small amounts (less than 5%) of alloying elements such as chromium, nickel, molybdenum, vanadium, and manganese, which enhance their mechanical properties.

Question 43

2

Q: What are the main types of low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 43

A: The main types of low alloy steels include high-strength low-alloy (HSLA) steels, quenched and tempered steels, and weathering steels.

Question 44

3

Q: What is the primary use of high-strength low-alloy (HSLA) steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 44

A: HSLA steels are used in structural applications such as bridges, buildings, and pipelines due to their excellent strength-to-weight ratio and corrosion resistance.

Question 45

4

Q: What are the properties of quenched and tempered low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 45

A: Quenched and tempered low alloy steels have high strength and toughness, achieved through heat treatment processes. They are used in demanding applications such as heavy machinery and military equipment.

Question 46

5

Q: What are weathering steels, and where are they commonly used?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 46

A: Weathering steels, also known as COR-TEN® steel, have enhanced corrosion resistance due to the addition of copper. They are commonly used in outdoor structures like bridges and buildings.

Question 47

6

Q: How does the addition of chromium affect low alloy steel?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 47

A: Chromium improves hardness, wear resistance, and corrosion resistance, making it ideal for applications requiring durability and exposure to harsh environments.

Question 48

7

Q: What effect does nickel have on low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 48

A: Nickel enhances toughness and impact strength, especially at low temperatures. This makes nickel-containing low alloy steels suitable for cold climates and critical structural applications.

Question 49

8

Q: What is the weldability of low alloy steels compared to carbon steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 49

A: Low alloy steels are generally more difficult to weld than carbon steels due to their higher alloy content, which increases hardness and the risk of cracking. Preheating, controlled cooling, and post-weld heat treatment may be required.

Question 50

9

Q: What welding precautions are necessary for low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 50

A: When welding low alloy steels, it is important to control heat input, use low-hydrogen electrodes, and follow preheating and post-weld heat treatment procedures to prevent cracking and maintain toughness.

Question 51

10

Q: Why is preheating important for welding low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 51

A: Preheating reduces the thermal gradient between the weld and the base metal, minimizing the risk of cracking by reducing hardness in the heat-affected zone (HAZ).

Question 51

11

Q: How does post-weld heat treatment (PWHT) affect low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 51

A: PWHT relieves internal stresses, reduces hardness in the heat-affected zone, and improves toughness, helping to prevent cracking after welding.

Question 52

12

Q: What is the effect of carbon content on the weldability of low alloy steels?

Objective 5: Identify the types, properties, and weldability of low alloy steels

Answer 52

A: Higher carbon content in low alloy steels increases the risk of hardness and cracking during welding, making it important to follow specific welding procedures to ensure weld quality.

Question 53

1

Q: What are high strength, low alloy steels (HSLA)?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 53

A: HSLA steels are a type of low alloy steel designed to provide better mechanical properties, such as strength and toughness, while maintaining a lighter weight compared to traditional carbon steels. They contain small amounts of alloying elements like chromium, nickel, and molybdenum.

Question 54

2

Q: How does the strength-to-weight ratio of HSLA steel compare to regular carbon steel?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 54

A: HSLA steel has a higher strength-to-weight ratio than carbon steel, allowing for lighter, more efficient structures without compromising strength.

Question 55

3

Q: What are the key mechanical properties of HSLA steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 55

A: The key mechanical properties of HSLA steels include high tensile strength, toughness, good formability, and resistance to corrosion and atmospheric conditions.

Question 56

4

Q: Why is HSLA steel used in construction and structural applications?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 56

A: HSLA steel is used in construction because it offers high strength and durability while being lighter than traditional carbon steel. This makes it ideal for large structures like bridges, buildings, and pipelines.

Question 57

5

Q: What makes HSLA steels more resistant to corrosion compared to regular carbon steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 57

A: The addition of alloying elements such as chromium and copper improves the corrosion resistance of HSLA steels, making them suitable for applications exposed to the elements, such as bridges and outdoor structures.

Question 58

6

Q: How does the weldability of HSLA steels compare to carbon steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 58

A: HSLA steels generally have good weldability, but their higher strength and alloying elements can make them more prone to cracking in the heat-affected zone (HAZ). Proper preheating and post-weld heat treatment may be required to prevent weld defects.

Question 59

7

Q: What precautions should be taken when welding HSLA steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 59

A: When welding HSLA steels, it is important to control heat input, use low-hydrogen electrodes, and apply preheating and post-weld heat treatment to reduce the risk of cracking and ensure proper toughness in the heat-affected zone.

Question 60

8

Q: What is the effect of heat input on the weldability of HSLA steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 60

A: Excessive heat input can cause excessive softening or hardening of the heat-affected zone, leading to reduced strength and toughness. Proper control of heat input is critical when welding HSLA steels.

Question 61

9

Q: How does preheating benefit the welding of HSLA steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 61

A: Preheating helps reduce thermal stress and prevent rapid cooling during welding, minimizing the risk of cracking in the heat-affected zone, especially in thicker HSLA materials.

Question 62

10

Q: In what industries are HSLA steels commonly used?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 62

A: HSLA steels are commonly used in industries such as construction, automotive, and shipbuilding, as well as for pipelines, pressure vessels, and heavy machinery where strength and weight savings are important.

Question 63

11

Q: What role do low-hydrogen filler metals play in welding HSLA steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 63

A: Low-hydrogen filler metals help prevent hydrogen-induced cracking during the welding of HSLA steels by reducing the amount of diffusible hydrogen introduced into the weld.

Question 64

12

Q: Why might post-weld heat treatment (PWHT) be necessary for HSLA steels?

Objective 6: Identify the properties and weldability of high strength, low alloy steels (HSLA)

Answer 64

A: Post-weld heat treatment helps to relieve residual stresses, improve toughness, and reduce the risk of cracking in the heat-affected zone, especially in high-strength HSLA steels.

Question 65

1

Q: What does the AWS (American Welding Society) classification system for alloy steel filler metals represent?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 65

A: The AWS classification system for alloy steel filler metals indicates the tensile strength, weldability, and composition of the filler metal. It is typically represented as “E” followed by numbers and letters, where the “E” stands for electrode.

Question 66

2

Q: What does the CSA (Canadian Standards Association) classification system for alloy steel filler metals represent?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 66

A: The CSA classification system is similar to the AWS system but uses metric measurements. It provides information on tensile strength, welding position, and composition, often matching AWS classifications for compatibility.

Question 67

3

Q: What do the first two digits in the AWS classification (e.g., E7018) represent?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 67

A: The first two digits in AWS classifications indicate the minimum tensile strength of the weld metal in thousands of pounds per square inch (psi). For example, “70” in E7018 indicates a minimum tensile strength of 70,000 psi.

Question 68

4

Q: What does the third digit in AWS classifications indicate (e.g., E7018)?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 68

A: The third digit in the AWS classification represents the welding positions that the electrode can be used in. A “1” indicates all positions, while a “2” indicates flat and horizontal positions only.

Question 69

5

Q: What does the fourth digit in AWS classifications represent?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 69

A: The fourth digit in AWS classifications specifies the type of flux coating and the recommended current type (AC, DC, or both). It also provides information about the operating characteristics of the electrode.

Question 70

6

Q: What is the AWS classification for a low-hydrogen electrode used for high-strength steels?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 70

A: The AWS classification for a low-hydrogen electrode used for high-strength steels is typically E7018, where “E” stands for electrode, “70” indicates 70,000 psi tensile strength, “1” means all-position welding, and “8” indicates low-hydrogen flux and compatibility with AC or DC.

Question 71

7

Q: How does the CSA classification E4918 correspond to AWS E7018?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 71

A: The CSA classification E4918 is equivalent to AWS E7018, with “49” representing 490 megapascals (MPa) of tensile strength (which equals 70,000 psi), and “18” indicating a low-hydrogen, all-position electrode suitable for both AC and DC welding.

Question 72

8

Q: What is the significance of supplementary designators in AWS and CSA filler metal classifications?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 72

A: Supplementary designators, such as “H4” or “R”, are used in both AWS and CSA classifications to provide additional information about hydrogen content (e.g., “H4” means low hydrogen) or moisture resistance (“R”).

Question 73

9

Q: What does the supplementary designator “H4” indicate in AWS and CSA filler metal classifications?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 73

A: “H4” indicates that the filler metal contains a maximum of 4.0 ml of diffusible hydrogen per 100 grams of weld metal, which reduces the risk of hydrogen-induced cracking.

Question 74

10

Q: What does the “R” suffix indicate in AWS and CSA filler metal classifications?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 74

A: The “R” suffix indicates that the electrode has a coating designed to resist moisture absorption, important for preventing hydrogen-induced cracking in critical applications.

Question 75

11

Q: What are the typical applications of E80XX series electrodes classified by AWS?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 75

A: E80XX series electrodes are used for welding high-strength, low-alloy steels in industries such as construction, pipelines, and pressure vessels, where high tensile strength and toughness are required.

Question 76

12

Q: What information is provided by the last two digits of CSA filler metal classifications (e.g., E4918)?

Objective 7: Identify alloy steel filler material classifications in accordance with AWS and CSA specifications

Answer 76

A: The last two digits of CSA filler metal classifications indicate the type of flux coating, current compatibility, and welding positions, similar to the AWS system. For example, “18” means a low-hydrogen electrode suitable for all positions and both AC/DC current.

Question 77

1

Q: What are low alloy steel filler metals used for?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 77

A: Low alloy steel filler metals are used to weld low alloy steels that require enhanced strength, toughness, and resistance to environmental conditions such as corrosion and high temperatures.

Question 78

2

Q: What are the typical applications of low alloy steel filler metals?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 78

A: Low alloy steel filler metals are commonly used in industries such as construction (bridges, buildings), pressure vessels, pipelines, power plants, automotive, and aerospace for components requiring high strength and durability.

Question 79

3

Q: What is the AWS classification for low alloy steel filler metals?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 79

A: Low alloy steel filler metals are typically classified under the AWS E80XX series (e.g., E8018) for electrodes, which indicates high tensile strength and specific alloying elements to match the base metal properties.

Question 80

4

Q: What are ER80S series filler metals used for?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 80

A: ER80S series filler metals are solid wires used for gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW) of low alloy steels, offering good mechanical properties for high-strength, low alloy applications.

Question 80

5

Q: Why are low alloy steel filler metals with chromium used?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 80

A: Low alloy steel filler metals with chromium improve hardness, corrosion resistance, and wear resistance, making them suitable for applications like high-stress structural components and pressure vessels.

Question 81

6

Q: What is the application of low alloy steel filler metals containing nickel?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 81

A: Nickel-containing low alloy steel filler metals enhance toughness and impact strength, especially at low temperatures. They are used in pipelines, offshore platforms, and other applications exposed to cold environments.

Question 82

7

Q: What are molybdenum-containing low alloy steel filler metals used for?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 82

A: Molybdenum-containing filler metals are used for welding low alloy steels that require high strength, hardness, and resistance to high temperatures, such as components in power plants and pressure vessels.

Question 83

8

Q: What is the significance of low-hydrogen filler metals for low alloy steels?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 83

A: Low-hydrogen filler metals help prevent hydrogen-induced cracking during welding, which is especially important for high-strength, low alloy steels that are prone to cracking in the heat-affected zone (HAZ).

Question 84

9

Q: In which industries are low alloy steel filler metals containing vanadium commonly used?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 84

A: Low alloy steel filler metals with vanadium are used in industries like construction and heavy machinery manufacturing, where increased strength and toughness are essential for components like cranes, bridges, and structural beams.

Question 85

10

Q: What precautions are needed when selecting low alloy steel filler metals for welding?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 85

A: When selecting low alloy steel filler metals, it is important to match the alloying elements of the filler metal with the base metal to ensure compatible mechanical properties. Proper welding procedures, such as preheating and controlled cooling, are also necessary to avoid cracking.

Question 86

11

Q: What are the typical properties enhanced by using low alloy steel filler metals?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 86

A: Low alloy steel filler metals improve tensile strength, toughness, corrosion resistance, and high-temperature performance, making them ideal for critical applications in harsh environments.

Question 87

12

Q: What are the typical filler metals used in pipeline welding?

Objective 8: Identify low alloy steel filler metals and their applications

Answer 87

A: In pipeline welding, low alloy steel filler metals such as E8010 or E8018 are often used due to their toughness, strength, and ability to withstand harsh environmental conditions, including low temperatures and high pressures.