45 # steel and 40Cr steel quenched and tempered heat treatment process
Source: precision seamless steel pipe plant in Shandong http: //www.sdlggg.com Tags: precision seamless tube; precision seamless; precision seamless steel pipe plant in Shandong
Quenched and double heat treatment and quenching and tempering, its purpose is to make the workpiece has good mechanical properties. Reinforced connecting apply 45 # precision steel
Quenched and tempered steels are carbon steel and alloy quenched and tempered steel two categories, either carbon steel or alloy steel, the carbon content is more stringent control. If the carbon content is too high, the strength of the workpiece after quenching, although high, but the toughness is not enough, as the carbon content is too low, toughness and lack of strength. In order to get a good piece quenched overall performance, the general control of the carbon content of 0.30% to 0.50%. reinforced connecting apply 45 # precision steel
When the tune of hardened, requires the entire cross section of the workpiece quenching, the workpiece obtained as fine needles quenched martensite microstructure dominated by tempering, to obtain an even tempered sorbite microstructure dominated. small factories do not every furnace metallurgical analysis, generally for hardness testing, that is to say, the hardness after quenching must reach quenched hardness of the material, the hardness after tempering Figure requirement to check reinforced connecting apply 45 # precision steel tubes.
Workpiece quenching operation must be in strict accordance with process documents executed during the operation we just mention some views on how to implement the process.
1, 45 of quenched and tempered steel
No. 45 steel is carbon steel, hot and cold processing performance are good, good mechanical properties, and low prices, wide source, so widely used. Its biggest weakness is the low hardenability, and require a relatively large cross-sectional dimensions of the workpiece high should not be used.
Apply reinforced connections 45 45 # precision steel pipe quenching temperature in A3 + (30 ~ 50) ℃, in practice, the upper limit is generally taken. High quenching temperature so that the workpiece can be heated faster, reduce surface oxidation, and can improve work efficiency. To make the workpiece austenite homogenization, we need sufficient holding time. If the actual installed furnace capacity, would be appropriate to extend the holding time. Otherwise, there may be insufficient hardness due to uneven heating caused by the phenomenon. However, the holding time is too long, will also appear coarse grains, oxidation and decarbonization serious shortcomings, the impact quenching quality. We believe that as installed furnace is greater than a predetermined process documents, heating holding time for an extended 1/5.