Common technical standards for domestic valve materials by solution treatment austenitic - ferritic steel bar or specimen mechanical properties a

GB / T

20878

In the serial number

Unite

digital

Code

Provisions non-proportional extension

Strength R P0.2 b / (N / mm 2 )

Tensile strength R m

/ (N / mm 2 )

Elongation at break A

/%

rate of reduction in area

Z c /%

Impact absorption function A ku2 d

/ J

  a Table 7 applies only to rods of diameter, length, thickness or opposite edge distance less than or equal to 75 mm. Steel bars larger than 75 mm may be forged into a 75 mm sample test or negotiated by both supply and demand to provide values ​​that allow the mechanical properties to be reduced.

  b provides non-proportional extension strength and hardness, only when the demand side (specified in the contract) was measured, and the supplier can be based on the size or state of the steel rod or a determination of hardness.

  c flat steel does not apply, but the demand side, both parties determined by the supply and demand.

  d diameter or an opposite side distance of 16mm or less round, hexagonal, octagonal, and the steel edge length equal to or less than 12mm thickness of the steel, flat not impact test.