Nb / t47008-2017:
Forgings are divided into four grades I, II, II and IV. The inspection items of each grade are as follows:
Forging level inspection item inspection quantity
I hardness (HB): check one by one;
II drawing and impact: same smelting furnace number, same furnace batch, sampling inspection for each batch -- pieces;
I. drawing and impact: same smelting furnace number, same furnace batch, sampling inspection for each batch -- pieces. Ultrasonic testing: piece by piece;
IV. tension and impact: inspection piece by piece, ultrasonic inspection: inspection piece by piece;
GB 150.4-201 1 stipulates:
6.1.3 the following steel forgings shall be grade III or IV:
It is used as cylinder, ring and bowl forgings of vessel shell and head.
Low alloy steel forgings with a nominal thickness greater than 300 mm.
Low alloy steel forgings with lower limit of standard tensile strength equal to or greater than 540Mpa and nominal thickness greater than 200mm.
Use low temperature steel forgings with temperature lower than - 20 ° C and nominal thickness greater than 200mm.
6.1.4 for 20MnMoNb, 20MnNiMo, 12cr2mo1v and
12cr3mo1v grade II or IV steel forgings. The design documents shall specify that the steel forgings shall be made in batches (grade II) or piece by piece
(class IV) high temperature tensile test at design temperature with yield strength value as shown in Appendix B.
Hg / T 20592-2009 stipulates:
4.0.2 the level and technical requirements of forgings (including forged and rolled pieces) for pipe flange shall meet the requirements of the following two items:
If it meets one of the following conditions, it shall meet the requirements of forgings of class II or above:
The nominal pressure is greater than or equal to PN100;
Chromium molybdenum steel forgings with nominal pressure greater than PN40;
Ferritic steel forgings with nominal pressure greater than PN16 and operating temperature less than or equal to - 20 ° C.
In addition to the above provisions, forgings with nominal pressure not greater than pn63 shall meet the requirements of forgings of class II or above.
Hg / T 20585-2011 stipulates:
6.0.8 forgings for low temperature pressure vessels shall be in accordance with Nb / T 47009 and
Stainless steel and heat resistant steel forgings for pressure equipment (Nb / T 47010), shall not be lower than grade I requirements, design pressure
When the force is greater than or equal to 1.60mpa, it shall not be lower than level II.