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Dear teachers, do forgings with grades II, III, and IV in Table 2 of NB/T47008-2017 require hardness testing? I think it is necessary. What do you all think?
Hardness indicates a material’s ability to resist local plastic deformation, indentation, or scratching; it is a comprehensive property of materials that reflects aspects such as their elasticity, plasticity, strain hardening, strength, and toughness. There is a corresponding relationship between hardness and tensile strength. Tensile testing, impact testing, and ultrasonic testing have already been done; conducting a hardness test further is not very meaningful. Usually, in situations such as maintenance or other cases where it’s not possible to take samples for tensile or impact testing, a hardness test alone is sufficient. Here is an article you can refer to: https://mp.wei*n.qq.com/s/dWAq9ShDKiqbrrCj0vCzHA
The standards have already been established; what more is there to doubt?: victory:
So, do you think a warranty certificate for second-stage forging should specify the hardness?
Standards are meant to serve as a reference; managers can require standards that are higher than those!
For forgings of grades II, III, and IV, additional hardness testing is optional; it’s not necessary
According to the standard requirements, hardness testing is not required for grades II, III, and IV, as more accurate control methods than hardness testing are used