Knowledge of quenching process and material processing of science No. 45 steel

Brief description of No. 45 steel 45# is the grade of steel, which is a high-quality carbon structural steel, corresponding to the Japanese standard S45C, the American standard: 1045, and the German standard C45. It is characterized by higher strength and deformation resistance than ordinary A3 steel. Its chemical composition element ratio (%): carbon C: 0.42 ~ 0.50; chromium Cr: ≤ 0.25; manganese Mn: 0.50 ~ 0.80; nickel Ni: ≤ 0.25; phosphorus P: ≤ 0.035; sulfur S: ≤ 0.035; silicon Si: 0.17 ~ 0.37 No. 45 steel quenching process No. 45 steel quenching process No. 45 steel quenching process After quenching, the highest can reach HRC55, of course, the heat treatment process and material composition are required to be correct. However, in order to achieve the hardness of HRC55, 45 steel can only be tempered at low temperature. The tempered martensite obtained is relatively coarse, the material is hard and brittle, and the use is not meaningful. Therefore, the hardness of 45 steel after quenching is generally controlled at about HRC50. If there is no requirement for wear resistance, quenching and tempering is more commonly used. 1. Quenching treatment: Recommended heat treatment temperature: normalizing: 850℃, quenching: 840℃, tempering: 600℃. According to general heat treatment specifications, the relationship between heat treatment system and hardness is roughly as follows: Quenching temperature: 840 ℃ water quenching; (1) 150 ℃ tempering, the hardness is about 57HRC; (2) 200 ℃ tempering, the hardness is about 55HRC; (3) Tempered at 250℃, the hardness is about 53HRC; (4) Tempered at 300℃, the hardness is about 48HRC; (5) Tempered at 350℃, the hardness is about 45HRC; (6) Tempered at 400℃, the hardness is about 43HRC; ( 7) Tempered at 500 ℃, the hardness is about 33HRC; (8) Tempered at 600 ℃, the hardness is about 20HRC. 2. Quenching and tempering treatment: The parts after quenching and tempering treatment have good comprehensive mechanical properties and are widely used in various important structural parts, especially those connecting rods, bolts, gears and shafts that work under alternating loads. But the surface hardness is low and not wear-resistant. Quenching and tempering + surface quenching can be used to improve the surface hardness of parts. Quenching process of No. 45 steel No. 3 and No. 45 steel should not adopt the heat treatment process of carburizing and quenching: The hardness of No. 45 steel quenched and tempered parts after quenching should reach HRC56~59, and the possibility of large cross-section is lower, but it cannot be lower than HRC48, otherwise , it means that the workpiece has not been completely quenched, and sorbite or even ferrite structure may appear in the structure. This structure is still retained in the matrix through tempering, and the purpose of quenching and tempering cannot be achieved. The high temperature tempering of No. 45 steel after quenching, the heating temperature is usually 560~600℃, and the hardness is HRC22~34. Because the purpose of quenching and tempering is to obtain comprehensive mechanical properties, the hardness range is relatively wide. However, if the drawings have hardness requirements, the tempering temperature must be adjusted according to the requirements of the drawings to ensure the hardness. For example, some shaft parts require high strength and high hardness; while some gears and shaft parts with key grooves need to be milled and inserted after quenching and tempering, so the hardness requirements are lower. Regarding the tempering holding time, it depends on the hardness requirements and the size of the workpiece. After years of accumulated experience, Kehua Induction Heating Equipment tells us that the hardness after tempering depends on the tempering temperature, which has little to do with the tempering time, but it must be back through. Generally, the tempering and holding time of the workpiece is always more than one hour. The above is the quenching process of No. 45 steel organized by Xiaobian for you. The process is similar, but there are very few manufacturers who strictly implement the process requirements. Kehua Induction Heating Equipment specializes in processing steel structures. Welcome to visit if necessary!
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