Objective 04: Metal Specifications Flashcards
Who determines which metals may be used to construct pressure vessels, pressure piping, and process piping systems?
ASME
From whom does ASME adopt material specifications?
ASTM
After development of ASME codes, who approves them?
ANSI
When can an unidentified metal be used in a plant application?
Never
Who determines material specification and selection in plant application?
Design Engineer
Why should materials only be ordered from reputable suppliers?
To avoid counterfeit products that are inferior
What are the 6 categories of metals?
- Low Carbon Steel (carbon content <0.30%)
- Medium Carbon Steel (carbon content 0.30-0.60%)
- High Carbon Steel (carbon content 0.60-1.5%)
- Cast Iron (carbon content 2-6%)
- Alloy Steels
- Non-Ferrous Metals
What are Non-Ferrous Metals in use?
- Copper
- Aluminum
- Brass
- Nickel
- Tungsten
- Zirconium
What metal is most piping in a power plant made of?
Low carbon or alloy steel
How is metal chosen for a particular job?
Based on safety and metal survivability to ensure the metal can withstand the most extreme environment it will be used in and still retain a factor of safety.
What does an engineering piping schedule call for?
ASTM “A” or “B” number material of specified grade, dimension, and schedule
ASTM “A” Material
Carbon Steels and Alloys
ASTM “B” Material
Non-Ferrous Metals
Material Test Reports (MTRs)/Certificates of Testing
Comprehensive chemical and physical analysis of the metal used to manufacture the pipe or fitting that are made available by the vendor to the puchaser upon request
Where do MTRs originate?
The smelter where the metal was made
Heat Number
Identification number for each batch of metal (or alloy) and all the products made from that batch that follows products made from these materials throughout their lieftime, including being copied unto lengths of pipe cut from the original length
What information do MTRs contain?
- Pipe or Fitting Identification
- Heat Number of the metal
- Chemical Composition
- ASME or ASTM Specification Number
- Grade
- Schedule
- Tensile Strength
- Yield Point of Metal
- Results of Specialized Testing, e.g. Charpy Test
- Any Heat Treatment Process the part underwent
What is the process by which ASME specifies which metals may be used to construct pressure vessels, pressure piping, and process piping systems?
- ASME adopts material specifications developed by ASTM
- ASME lists the reviewed and approved materials in the ASME BPVC
- ASME codes are approved by ANSI
For whom are the extensive complexity of ASME codes regarding material specifications intended?
Professional engineers who design power and processing plants
Why should power engineers be familiar with basic metal specifications?
May have to monitor the suitability of the materials used. The chief power engineer may be responsible for purchasing piping, fittings, and equipment to replace or repair plant systems.
