F6NM martensitic stainless steel cylinder-body forge piece and heat treatment method

Abstract

The invention relates to a F6NM martensitic stainless steel cylinder-body forge piece and a heat treatment method. According to the F6NM martensitic stainless steel cylinder-body forge piece and the heat treatment method, the high strength and the high low temperature impact toughness resistance can be met, cracks are avoided, and meanwhile, cracking and scrap of steel ingots during forging are avoided; and the F6NM martensitic stainless steel cylinder-body forge piece comprises, by mass, no more than 0. 04% of C, 0.30-0.50% of Si, 0.70-1.00% of Mn, 11.5-13.0% of Cr, 3.5-4.5% of Ni, 0.50-0.70%of Mo, 0.04-0.1% of V, no more than 0.020% of P and no more than 0.010% of S. The F6NM martensitic stainless steel cylinder-body forge piece has the advantages that the F6NM martensitic stainless steel cylinder-body forge piece after being subjected to component optimization adopts sectional-type constant-temperature slow heating, the charging temperature, the heating speed and the heat preservation time are strictly controlled, forging is strictly executed according to the new forging process, and heat treatment adopts the special heat treatment process of 550 DEG C constant-temperature heating, 1000 DEG C air quenching and three times of tempering at 690 DEG C, 630 DEG C and 590 DEG C. After production, product inspection dimensions confirm to the customer drawing requirements, a sampleis sampled and sent to a third party for being tested, the mechanical properties meet the index requirements, after multiple times of production, the mechanical properties of the F6NM martensitic stainless steel cylinder-body forge piece are all very stable, and the F6NM martensitic stainless steel production scrap risk is greatly reduced.

Description

technical field [0001] The invention relates to a F6NM martensitic stainless steel cylinder body with a diameter greater than 953mm and a length greater than 1385mm. It is required to meet high strength, high low temperature impact toughness, and avoid cracks. Disclosed are cracked and scrapped F6NM martensitic stainless steel cylinder forgings and a heat treatment method, belonging to the field of manufacturing stainless steel cylinder forgings. Background technique [0002] F6NM material is the material in ASTM A336 / A336M-09 "Standard for Alloy Steel Forgings for High Temperature Pressure Components" of the American Society for Testing and Materials. It belongs to martensitic stainless steel, and its chemical composition contains 13% Cr and 4% Ni, which is quite In the domestic brand 0Cr13Ni4Mo. [0003] F6NM material is a new type of martensitic stainless steel used in the manufacture of large castings and forgings. In today's increasingly stringent environmental protec...

AI Technical Summary

Problems solved by technology

However, F6NM martensitic stainless steel has poor thermal conductivity. If the furnace temperature is too high or the temperature rises too fast, large internal stress will be generated and small cracks will appear. After forging, the cracks will expand and lead to scrapping. It will produce reversed austenite structure, the tempering temperature has a great influence on the performance, and the mechanical properties are difficult to control

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