Effect Of Cold Drawing Process On Microstructures And Properties Of 304 Stainless Steel Wear-resistant Wire

The domestic wear resistant steel wire products are mostly hot rolled products of high manganese and high nitrogen austenitic stainless steel because of the cost factors.The average life span of the product is often shorter because the products are working in a special environment such as high wear and corrosion for a long time.304 austenitic stainless steel is a good alternative to wear resistant steel wire because it has excellent deformation induced martensitic transformation ability and excellent corrosion resistance.However,there are few studies on the deformation induced phase transition during the current 304 stainless steel cold machining,especially the cold-drawing process.Therefore,this study intends to use the commercial 304 stainless steel hotrolled disk as the raw material.Through the cold drawing forming technology to explore its feasibility as a wear resistant steel wire used in special environment such as deep well deep sea mining.This study has important reference significance for the development and practical application of domestic wearresistant steel wire.In this paper,we designed a multi group cold drawing scheme of 304 stainless steel wear-resistant wire.OM and TEM were used to observe the microstructure of the wear-resistant wire.The strengthening mechanism of the wire during drawing was analyzed.The mechanical and wear properties of wire were tested under different deformations.The wear mechanism was analyzed by SEM and EDS.The main conclusions are as follows:1.With the principle of large deformation low temperature annealing treatment,the average number of deformation is more than 20%.In the process of drawing control the annealing temperature is below 700 ?.After the last 1?2 lines,no annealing treatment is conducted.A cold drawn fiber structure with high cumulative deformation degree can be obtained.2.Achieved the domestic screen with ?2.3 mm target size cold drawn wire.Its cold drawing process:08 mm??7.2 mm(19%)??6.8 mm(28%)??05.8 mm(48%)??5 mm(61%)?annealing treatment(700?/20 min)??4.4 mm(23%)??3.9 mm(39%)?annealing treatment(700?/20 min)??3.4 mm(24%)??3 mm(41%)?annealing treatment(700?/20 min)??2.5 mm(31%)??02.3 mm(41%).The total deformation amount is 92%,and the maximum cumulative deformation amount is 61%.3.The increase of cold deformation causes the deformation of the structure to be elongated by the equiaxed grain.The grain is destroyed and the grain boundary is blurred,the final tissue is a cold drawn fibrous tissue,With the increase of deformation,the strength and hardness of the wire have increased,the elongation decreased.The result of XRD analysis shows that the transformation from austenite to ?-martensite occurs during the drawing.4.The cold deformation causes the dislocation entanglement to block the plastic deformation,and there is a small amount of deformation twins.With the increasing of the cumulative deformation,the number of deformed twins increases,and the plastic deformation is impeded by the twin method.With the increase of deformation,the deformation induced martensitic transformation occurs,and the strength and wear resistance of the wire are improved.5.The friction coefficient-time curve of 304 stainless steel has two stages.With the increase of the degree of cold deformation,the width and depth of the wear scar reduced,the wear rate and the average friction coefficient decreased,and the wear resistance improved.6.The dry wear mechanism of 304 stainless steel is the composite wear mechanism of abrasive wear,adhesive wear and oxidation wear.Adhesive wear is the main wear mechanism under low deformation.As the deformation increases,the wear and wear mechanisms become more serious,and the wear mechanism is changed to abrasive wear as the main wear mechanism.