Large diameter ring gear carburizing and quenching

Large diameter ring gear carburizing and quenching - 2020 07 - 14 flower of kudzuvine honor the exemption ( China metallurgical shan pressure heavy industry equipment co. , LTD. Heat treatment branch engineering office; China metallurgical shan hot working center of pressure heavy industry equipment co. , LTD) Branch recently, heat treatment was carried out on the two ring gear carburizing and quenching, 20 crni2mo material, technical requirements for tooth surface hardness of 56 ~ 60 HRC, the depth of carburizing layer 1. 8 ~ 2. 0 mm, the overall dimensions & phi; 1470mm× 145毫米( Inner hole & phi; 1313mm） And modulus of 14, tooth groove pitch for about 50 mm, inner hole distance according to the conventional heat treatment allowance and heat treatment process, appear easily due to the size of workpiece deformation occurred after quenching out-of-tolerance artifacts caused by discarded. 1. Preliminary analysis ( 1) Conventional heat treatment process allowance before carburizing common normal allowance 0. 8 mm+0. 1 mm, the rest of the face allowance unilateral 5 mm, for the low strength of gear ring structure, the process of allowance and methods there is no guarantee that the parts finished product size. （ 2) Now take measures to increase the heat treatment technology on margin and make a special tooling for carburizing and quenching of the parts. 2. Process to prepare, 1) Process allowance the pieces before carburizing process allowance: face allowance of 10 mm, base tangent allowance 0. 8毫米+ 0。 1 mm, tip diameter allowance 1 mm, inner hole according to the hole diameter of 62 mm allowance, and in 62 mm wide range ( φ 1281 mm) Drilling and tapping 8 & times; M12 thread hole to put the carburizing and quenching the tooling. （ 2) Carburizing and quenching equipment use flange tooling, size is shown in figure 1. Figure 1 carburizing and quenching equipment ( 3) Carburizing charging for (1) the brush surface carburization workpiece before carburizing coatings for seepage control protection. Figure 1 (2) the flange tooling before carburizing occlusal face under the artifacts, along the bottom surface under tooling & phi; 800 mm round welding & phi; 40mm× 155 mm round steel six place, prevent the upper end face carburizing and quenching heating process tooling subsidence deformation and can't support role during quenching, round steel with 4 & phi; 400 mm uniform hole stagger, the purpose of the hole is in the hole leakage after quenching. (3) to the closed end face tooling on end face occlusal tooling without the 4 & phi; Uniform hole is 400 mm, the rest of the dimensions are the same. (4) carburizing furnace spreader directly from & phi; 400 mm size carburizing under wear. （ 4) Difficulties due to the cargo loading and unloading after carburizing, carburizing and does not return after processing workshops, direct quenching. 3. Results after carburizing and quenching size before and after carburizing and quenching are shown in table 1. Table 1 size (before and after carburizing and quenching mm） 4. Increase the pieces after quenching due to aging heat treatment process before carburizing inner hole allowance is too big, to prevent processing to the front of the aging allowance after aging process, artifacts caused by the deformation and stress of the processing is too big size out-of-tolerance, therefore increase the aging process, aging before only machining inner hole, inner hole diameter of 18 mm allowance, other parts of the fixed knife, after waiting for aging and other parts for subsequent workpieces aging. 5. Conclusion by the production and use of specialized equipment and tooling, the thin wall ring gear final qualified, reach the pattern size and hardness requirements, the implementation of the measures for future similar artifacts carburizing and quenching of accumulated experience, directly bring good economic benefits, make a ring gear carburizing and quenching heat treatment process to mature. （ Source: heat treatment ecosystem)