AWS D3.5-93R

Question 1

Steel Manufacturing Processes

Answer 1

Ship steel is made primarily in basic oxygen furnaces (BOF), open-hearth furnaces, and electric furnaces. Only a few open-hearth furnaces operating today. Electric furnaces are used to make high-alloy specialty steels, steels for castings, and in conjunction w/ continuous casters they’re used to make small to medium sized shapes and some flat rolled products.

Question 2

Plates and Shapes

Answer 2

Plates are rolled in one of three types of rolling mills to produce sheared plates, universal mill plates, and continuous strip.

Question 3

Sheared plates

Answer 3

rolled on mills which have horizontal rolls only, are produced with irregular edges and ends which must be cut or sheared on all sides to produces a rectangular plate. rolled in both directions by rotating the slab at the roughing stand of the mill.

Question 4

Cross rolling

Answer 4

process of rolling sheared plates. provides the plate w/ more uniform longitudinal and transverse properties, and sheared plates are usually specified where stringent mechanical properties are required.

Question 5

Universal mill plates

Answer 5

rolled on mills with both horizontal and vertical rolls. vertical rolls provide the plate with a rolled edge which doesn’t require cutting to establish its width. universal mill plates are not cross-rolled, and as a result, the plates may have slightly lower ductility in the transverse direction. these plates are used where a finished edge is desirable.

Question 6

Continuous strip mill plates

Answer 6

made on a hot strip mill and can be furnished in coils or as flat rectangular products. these plates are used primarily for structural applications, cold-formed shapes, or on automated barge construction lines.

Question 7

Hot strip mill plates

Answer 7

may have directional properties b/w those of the sheared mill and universal mill products

Question 8

Structural shapes

Answer 8

are usually rolled on a mill similar to a universal plate mill

Question 9

Chemistry

Answer 9

steel is essentially a combination of iron manganese and carbon. The carbon content normally ranges b/w 0.05 - 1.00%, while the manganese content range is 0.25 - 1.00%. many other elements are added in relatively small amounts to vary the mechanical characteristics of the steel.

Question 10

Which categories do plate steels generally fall under?

Answer 10

carbon steel or an alloy steel

Question 11

Carbon steels

Answer 11

comprise those grades where no minimum content is specified or required for aluminum, born, chromium, cobalt, columbium (niobium), molybdenum, nickel, titanium, tungsten, vanadium, or zirconium, or any other element added to obtain a desired alloying effect.

Question 12

when specified, minimum copper does not exceed…

Answer 12

0.40%

Question 13

the maximum content specified for any of the following elements shall not exceed the percentages noted:

Answer 13

manganese 1.65, silicon 0.60, copper 0.60

Question 14

Alloy steels

Answer 14

comprise those grades which exceed the above limits, plus any grade to which any element other than those mentioned above is added for the purpose of achieving a specific alloying effect.

Question 15

Carbon steels usually have a lower…

Answer 15

base price than alloy steels and therefore are much more widely applied

Question 16

for structural applications, plates normally do no exceed…

Answer 16

0.30% carbon and 1.50% manganese

Question 17

effects of elements

Answer 17

the effects of commonly specified chemical elements on the properties of hot-rolled and heat-treated carbon and alloy plates are discussed here by considering the various elements individually. in practice the effect of any particular element will often depend on the quantities of other elements also present in the steel. for example, the total effect of a combination of alloying elements on the hardenability of a steel is usually greater than the sum of their individual contributions

Question 18

which element is the principal hardening element in steel?

Answer 18

carbon.

Question 19

what is the carbon level for plate steels?

Answer 19

generally less than 0.30%

Question 20

what are the preferred carbon levels for improved ductility, weldability, and toughness?

Answer 20

below 0.20%

Question 21

which element is present in all commercial steels?

Answer 21

manganese

Question 22

which element contributes significantly to strength and hardness in much the same manner but to a lesser extent as does carbon?

Answer 22

manganese

Question 23

what’s an important characteristic of manganese in steel?

Answer 23

it has the ability to decrease the critical cooling rate during hardening, thereby increasing the hardenability. the effect of manganese in this respect is greater than that of any of the other commonly used alloying elements

Question 24

which element is an active deoxidizer?

Answer 24

manganese. shows less tendency to segregate within the ingot than do most other elements

Question 25

which element is generally considered an impurity except where its beneficial effect on machinability and resistance to atmospheric corrosion is desired?

Answer 25

phosphorus