30CrNiMoNb protective steel

30CrNiMoNb steel code 6211 steel. It is still in the experimental protection stage.

603 steel: 30CrMnMoRE, standard GJB 31A-2000
616 steel: 22SiMn2TiB, standard GJB 1496B-2014
617 steel: 30CrNi2MnMoRE, standard GJB 31A-2000
675 steel: 30CrNi3MoV, standard GJB 31A-2000
685 steel: 30MnCrNiMo, standard GJB 8223-2014 Q/ASB 108-2010
695 steel: 42CrNiMoV, standard GJB 8486-2015
6211 Steel: 30CrNiMoNb, standard GJB 8486-2015

8Cr2Mo: GY5 high pressure steel, standard GJB 1496B-2014
26SiMnMo: GY4 high pressure steel, standard GJB 1496B-2014
32Mn2Si2A: Standard GJB 3166-1998

The precipitation phases at different austenitizing temperatures were studied, and the precipitation of Nb C in 6211 steel during hot rolling can effectively prevent the grain growth and make the substrate obtain fine original austenite grains. When the steel is quenched, when the quenching temperature is lower than 1050 ℃, the Nb C precipitation phase is partially dissolved in the austenite, but the undissolved Nb C can play a pinning effect, inhibit the growth of austenite grains, and ensure the 30CrNiMoNb steel. A fine-grained structure is obtained; when the temperature is higher than 1050 °C, the Nb C part is solid-dissolved in the austenite, and the undissolved part grows significantly, which weakens the pinning effect on the austenite grains, resulting in the long austenite grains. big.

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