Fine blanking is an efficient and economical processing technology which combines precision blanking and sheet metal forming to manufacture precision and complex stamping parts. Fine blanking requires the use of materials with good plasticity, low yield ratio, high elongation, good spheroidizing fine grain structure, and the general tensile strength is less than 600MPa.
Overview of fine blanking materials
Classification of fine blanking materials
Fine blanking material is one of the core elements of fine blanking technology, which requires uniform material and moderate hardness. At present, fine blanking materials mainly include steel, aluminum or aluminum alloy, copper or copper alloy, in which steel accounts for 90%, aluminum or aluminum alloy accounts for 8%, and copper or copper alloy accounts for 2%. Steel is the most widely used fine blanking material. According to the type of steel, it can be divided into carbon steel, alloy steel, cold formed high yield steel and stainless steel.
(1) carbon steel is divided into low carbon steel, medium carbon steel and high carbon steel.
1) Low carbon steel SPCC, spcc-1b, DC01, sae1010, SPHC are widely used in traditional hard disk voice coil motor bracket, gearbox friction material, air conditioning valve plate, etc. Its characteristics are: low silicon (≤ 0.05%), low carbon (≤ 0.1%), no lamellar pearlite, all free cementite. Therefore, heat treatment and recrystallization annealing is conducive to the fine blanking of the material, and good bright band can be obtained even in hot rolling state.
Low carbon steel s20c, sae1018, C15, 20mnb5, sae1020, s35c are mainly used in transmission friction plate, seat adjustment mechanism gear plate parts, engine flywheel and other parts. Its characteristics are: carbon content is 0.13% ～ 0.25%, manganese content is 0.5% ～ 0.9%. After spheroidizing annealing, flake pearlite is transformed into spherical shape, which has good plastic deformation ability, which is conducive to fine blanking gear parts. The manganese content of the material is higher than that of ultra-low carbon material, and the requirements of strength and wear resistance are achieved by quenching and carburizing.
2) S45C, S55C, c45e and sae1055 are commonly used in medium carbon steel, which are mainly used in automobile door lock, safety belt and chain industry. It is characterized by high carbon content (0.43% ～ 0.58%). The material must be spheroidized and annealed to have better plasticity. The material has higher strength and is generally quenched after stamping.
3) The carbon content of c60e, sae1060 and sk85 in high carbon steel is very high, which needs many times of heat treatment and rolling to achieve good spheroidization. It is mainly used in safety belt, bearing and other fields.
(2) among the alloy steels, the typical steel types are 16MnCr5, SCM435, 42CrMo4 and 51CrV4. The materials must be spheroidized to obtain good plasticity. If they are not treated, they are easy to brittle fracture. Generally, the production of plane parts with less complex shape is mainly produced, and the parts that are not suitable for complex deformation are mainly CrMo alloy. It is mainly used in automobile door lock system, engine system, clutch system, etc.
(3) the typical steel types of cold forming high yield steel are qste420tm, qste550, s460mc and saph440. These materials belong to low-carbon fine grain structural steel. Nb, V, Ti and other alloys are added into high manganese low-carbon steel to refine the structure, increase the strength and facilitate fine blanking. It is mainly used in seat adjuster guide plate, fork, cover plate and other parts.
(4) the typical stainless steel grade is 1.4016, which must have good carbide structure to facilitate stamping. It is mainly used for manufacturing exhaust pipe flange.
Comparison of properties and prices of fine blanking materials at home and abroad
With the development of domestic automobile industry, the pace of localization of fine blanking materials is speeding up. Many parts giants are in urgent need of localized supply of parts or materials, so as to reduce the pressure of cost reduction and delivery time. Domestic large steel mills are also aware of this demand. Leading companies such as Baosteel, Baosteel Research Institute and Meisteel Technology Center have invested a large number of manpower to research and develop new fine blanking hot rolling materials 。 The second echelon, such as Shougang, and the third echelon, such as LIANGANG in Loudi, Hunan Province, have invested a lot of manpower and material resources in fine blanking raw materials. The trend of material price has become transparent, and the price of foreign materials has decreased obviously; in terms of performance, domestic materials have been close to foreign materials. Taking the automobile industry as an example, the details are shown in Table 1: localization ratio of typical auto parts and foreign advantages.
Standards for enterprises to select high quality fine blanking materials
The standard of selecting high-quality fine blanking materials mainly considers three factors: price orientation, material application field and enterprise strategy. European and American series and Japanese series take quality as the leading factor, and they will select different states and standards of fine blanking materials according to different material applications. Generally, European and American systems have a set of mature material standards for reference by material manufacturers, while Japanese systems generally provide technical requirements. Domestic enterprises have not formed a standard system for fine blanking materials. As a fine blanking material manufacturer, it usually recommends the appropriate material according to the application field of the material and the follow-up process of the fine blanking manufacturer. See Table 2 for details.
2020-10-17