Material low-temperature impact
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I would like to ask: according to Table 4 of GB150.2, which specifies the minimum operating temperature for plates, the minimum temperature for performing impact tests on 10mm-thick Q345R material at 0 degrees Celsius is -20 degrees. So, if an impact test is conducted at -30 degrees Celsius and the impact value is at least 20 J, can this material still be used at -30 degrees Celsius? Is it still the case that this table allows a minimum temperature of only -20 degrees?
The original poster’s understanding is still incorrect; the standard specifies that the minimum operating temperature for this material is -20°C, and materials suitable for lower temperatures should be used below that threshold. Moreover, the material standards stipulate that even when subjected to low-temperature impact testing, the impact value must meet the values specified in the standards; it is not allowed for this value to decrease.
Thank you. Additionally, according to GB150, the impact value should be no less than 20 J when the lower limit of the tensile strength is less than or equal to 450 MPa; this requirement has not been reduced. Are there any other standards that specify impact values?
Oh, I found it; according to GB713, it should be no less than 41J
The requirements for raw materials must first meet the material standards; the regulations set by GB150 represent the minimum threshold, with general material standards being higher than this. The minimum value specified in GB150 applies to welds.