MIM Sintering parts

With iron powder as the main raw material, adding different alloying elements and using different preparation processes, different types of sintered parts with different mechanical properties, meeting the needs of users and widely used in the market can be obtained.From the powder metallurgy products awarded by China association of mechanical parts industry in 2016, it can be seen that the excellent sintered parts performance is based on the performance of raw and auxiliary materials.Among the winning products of 2016 excellent new products of Chinese mechanical parts, there are the following 11 representative parts.

(1) EA888 sprocket set.The project includes crankshaft sprocket, oil pump sprocket, intermediate shaft sprocket and balanced shaft sprocket.All 4 sprockets require surface densification, with surface density greater than 7.5g /cm3 and density layer depth greater than 0.3mm.The surface densification technology is adopted to form a fully dense layer on the surface of parts, which can improve the hardness, wear resistance and service life of parts.The raw materials used are fe-mo, Ni, Mn and C.

(2) T5D transmission synchronizer tooth hub.The heat treatment surface hardness of the product reaches 500 ~ 950 HV0.1, the depth of dense layer is 0.5 ~ 2.0 mm (450 HV0.1), and the basic hardness is greater than 220 HV10.The material composition standard was QJ/GAC 1110.025.Density 7.0 g/cm3 or above;The waist groove cannot have the draft Angle;Tensile strength 590 MPa.The raw materials used are fe-ni-c.

(3) camshaft timing sprocket.This product is a thin plate sprocket with a large diameter to height ratio in the VVT field, and its outer teeth and lock pin holes need high-frequency quenching, with high machining precision of the end face.Key performance indicators for: lock pin hole position ϕ 0.1 mm, the mold guarantee;Turning the lock pin hole of ϕ flatness 0.04 mm, 89.0 mm below roughness Ra is 1.25 mm.The raw materials used are fe-mo, Cu and C.

(4) VVT stator.The heat treatment surface hardness of the product is 500 ~ 950 HV0.1, the depth of the dense layer is 0.5 ~ 2.0 mm (450 HV0.1), and the basic hardness is greater than 220 HV10.The material composition standard was QJ/GAC 1110.025.Density 7.0 g/cm3 or above;The waist groove cannot have the draft Angle;Tensile strength 590 MPa.The raw materials used are fe-mo and Ni.

(5) rotor of transmission oil pump.Inner rotor density 6.8 ~ 7.2 g/cm3, hardness 70 HRB, contour 0.025 mm, height tolerance 0.005 mm;The density of the outer rotor is 6.7 ~ 7.1 g/cm3, the hardness is 70 HRB, the profile of the tooth tip is 0.025mm, and the height tolerance is 0.005mm.Through the control of forming, sintering, finishing and clever mold design, the tooth profile of the inner and outer rotor can reach the requirement of 0.025mm;At the same time to improve the cleaning process, to achieve high cleanliness requirements.The raw materials used are: inner rotor fn-0208-30, outer rotor fc-0205-40.

(6) manual transmission interlock block.This product more than 6.8 g/cm3 density, the opening width ϕ (8.165 + 0.075) mm, use DORST equipment and forming powder displacement function.Adopt powder metallurgy forming to sintering hardening to complete directly, do not rely on machining milling to ensure the requirements of opening width and other dimensions.The raw material used is SINT C32.

(7) timing exhaust camshaft pulley.This product more than 6.6 g/cm3 density, vertical degree is less than 0.025 mm, timing angles (217.38 + 0.25) °, beating all tooth diameter less than 0.15 mm, taper 0.15%, imbalance degree (58 + 7)/kg (g · cm).The raw material used is fc-0205.

(8) VVT high-precision rotor.The product has a density of 6.8 g/cm3 or more, a cleanliness of 2 mg or less, an outer diameter of + / -0.02mm, a full length of (27.000 + / -0.008) mm, which is combined with the stator. By taking advantage of the characteristics of incomplete sintering in powder metallurgy, the side hole and cross hole of green billet processing are carried out.

(9) engine VVT stator.This product is the part of variable valve timing system, which adopts CNC powder forming technology, unique sintering technology and different shaping allowance to ensure the dimensional accuracy and roundness after shaping.The raw material used is sint-d11.

(10) double row sprockets for crankshaft.This product is the first double-row sprocket with staggered upper and lower tooth shapes, with a density of 7.0-7.1g /cm3, a cleanliness of 0.92mg, a tooth hardness greater than 68hra, and a microhardness of 680hv0.1.

(11) balance shaft driven gear assembly.The product is made up of two different powder metallurgy products bonded together by rubber. The product has certain elasticity, which can effectively reduce the vibration of the whole car and improve the driving comfort.Density 6.8 g/cm3 or above, heat treatment hardness 65 ~ 75 HRA, gear accuracy 6.The raw and auxiliary materials are fe-cu-c and rubber.