Strengthening and toughening of new type of gold-containing steel with large hardness bolt frame

The effect of quenching temperature on hardness and grain size is the effect of quenching temperature on the hardness and grain size of 22Cr2Ni4MoV steel. The quenching cooling medium is diesel. It can be seen that the influence of quenching temperature on hardness and grain size is consistent, reaching the highest at 850900e, the hardness value reaches 47HRC, and the grain size reaches 815. Then, as the quenching temperature increases, the hardness is especially grain. The degree has dropped significantly. Thus, 850900e is selected as the quenching temperature of the steel grade. The following tests were performed using 850e quenching and diesel cooling.

Effect of quenching temperature on hardness and grain size of 22Cr2Ni4MoV steel 11 Hardness 21 grain size The effect of tempering temperature on hardness and impact toughness is the effect of tempering temperature on hardness and impact toughness of Cr2Ni4MoV steel, low temperature below 250e During the tempering phase, the hardness and impact toughness decrease at a very slow rate. After the tempering temperature is higher than 250e, the hardness decreases at a faster rate with the tempering temperature increasing; while the impact toughness decreases rapidly after 250e, reaching the lowest point at about 480e, the impact energy is 35J; tempering temperature After reaching 500e, the impact toughness rises linearly with the increase of tempering temperature, and a temper brittle zone appears in 300550e.

The effect of tempering temperature on strength and plasticity is the effect of tempering temperature on the strength and plasticity of 22Cr2Ni4MoV steel. The tensile strength and yield point decrease linearly with the increase of tempering temperature, but the shrinkage and elongation are in There is a small trough in the 250500e interval, which is basically consistent with the fragile zone described above.

The steel has good hardenability, and the martensite structure can be obtained by air cooling, a is the martensite structure obtained by air cooling after the sample is forged; b is the ferrite body obtained after tempering 920e normalized +680e tempering + Pearlite structure; c is martensite + trace residual austenite structure obtained by 850e oil quenching; d is tempered martensite + trace residual austenite obtained by 850e quenching + 200e tempering; e is 850e quenching + 480e The tempered sorbite structure obtained by tempering. f is the case of martensite structure and grain boundary obtained by quenching at 975e.

Discussion 22Cr2Ni4MoV steel is a kind of high-hardenability low-carbon alloy steel. After forging, the martensite structure is obtained. a, its hardness is high, the grain size is coarse, and the grain size is about 2, which should be normalized and tempered. In order to obtain the ferrite + pearlite structure, see b. After treatment, the hardness is 2224HRC, and the grain size is about 8 grades, which is prepared for subsequent processing and preparation.

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