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F11(X20CrMoVW12.1)系马氏体耐热钢,合金含量较高,特别是铬含量高达12%,很容易淬火,在焊接热循环作用下,易形成马氏体组织,脆性很大。因此,焊接必须保持在较高的预热温度下进行。一般要求超过钢材的马氏体转变温度以上。对 F11钢的予热温度应在350～450℃,过低容易发生裂纹;偏高又会导致焊缝的韧性下降。同时,焊后不能马上进行回火处理,必须冷至100～120℃,在此温度下,保持一定时间,使焊缝金属全部转变为马氏体后,再行回火,以便得到回火索氏体,这样焊缝才具有较高的冲击韧性。回火温度不能超过 AC_1相变点,
F11 (X20CrMoVW12.1) Department of martensitic heat-resistant steel, high alloy content, especially chromium content of up to 12%, it is easy to quench the weld heat cycle, easy to form martensite, a great brittleness. Therefore, the welding must be maintained at a higher preheating temperature. General requirements over the steel martensitic transformation temperature above. F11 steel preheating temperature should be 350 ~ 450 ℃, low prone to cracking; high and will lead to the decline in the toughness of the weld. At the same time, welding can not immediately tempering, must be cooled to 100 ~ 120 ℃, at this temperature, to maintain a certain period of time, the weld metal is transformed into martensite, and then tempering, in order to get the tempering cable Body, so that the weld has a higher impact toughness. Tempering temperature can not exceed AC_1 phase transition point,