Year1
- 产品规格：
- 齐全
Features
Medium carbon quenched and tempered steel cold heading die steel. The steel is moderately priced and easy to process. After appropriate heat treatment, it can obtain certain toughness, plasticity and wear resistance. The normalizing section promotes tissue spheroidization and is suitable for surface hardening treatments such as high-frequency quenching and flame quenching.
Application
After quenching and tempering, it is used to manufacture mechanical parts that bear medium load and medium speed, such as steering knuckles, rear axles of automobiles, and gears, shafts, worms, spline shafts, and centers on machine tools. After quenching and tempering at medium temperature, the sleeves are used to manufacture parts that bear high load, impact and medium speed operation, such as gears, spindles, oil pump rotors, slides, collars, etc. After quenching and tempering at low temperature, they are used to manufacture parts that bear heavy loads. , low impact and wear-resistant, parts such as worms, spindles, shafts, collars, etc. with physical thickness below Parts with high impact such as gears, sleeves, shafts, spindles, crankshafts, spindles, pins, connecting rods, screws, nuts, intake valves, etc. In addition, this kind of steel is suitable for manufacturing various transmission parts that undergo carbonitriding treatment, such as gears and shafts with larger diameters and good low-temperature toughness.
Nitriding treatment
Steel is a nitridable steel and the elements it contains are conducive to nitriding. After nitriding treatment, a higher surface hardness can be obtained. After quenching and tempering, the highest hardness after nitriding treatment can reach r~, that is, r~. Nitriding workpiece process route: forging - annealing - rough machining - quenching and tempering - finishing - stress removal - rough grinding - nitriding - fine grinding or grinding. Since the nitride layer is thin and brittle, it requires a higher-strength core structure. Therefore, quenching and tempering heat treatment must be performed first to obtain tempered sorbite to improve the mechanical properties of the core and the quality of the nitride layer. Soft nitriding is active nitriding.
Pay attention to preheating before welding steel to prevent internal chilling and quenching cracks in the weld due to heat dissipation from the matrix. It is best to add normalizing after welding and before tempering. It is easy to segregate during crystallization and is sensitive to crystallization cracks (a kind of hot crack). When welding, it is easy to crack in the arc crater and the concave part of the weld. When the carbon content is high and cooled quickly, it is easy to obtain a hardened structure (martensite structure) that is very sensitive to cold cracks. When the cooling rate is high, the overheated zone can easily form hard and brittle high-carbon martensite, which will cause the overheated zone to become embrittled.
Welding process
Generally, welding is performed in the annealing (normalizing) state.
, the welding method is not restricted
, use larger linear energy to appropriately increase the preheating temperature. Generally, the preheating temperature and interlayer temperature can be controlled between ~℃.
, Welding materials should ensure that the composition of the deposited metal is basically the same as that of the base metal. For example,
, quenching and tempering heat treatment should be carried out in a timely manner after welding. If it is difficult to perform quenching and tempering in time, intermediate annealing can be performed or kept at a temperature higher than preheating for a period of time to eliminate diffusible hydrogen and soften the tissue. For products with complex structures and many welds, an intermediate annealing can be performed after a certain number of welds are welded.
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