A method of manufacturing a spring products

 

The invention relates to the field of mechanical engineering and metallurgy and can be used in hardware industry in the manufacture of spring product type train of wire terminals. A method of manufacturing a spring products, mainly shaped spring steel containing 0,38...0,42% carbon, 1.5 to 1.8% silicon and 0.6...0.8% manganese includes heat treatment of rolled billets and/or products, calibration and cutting processing with subsequent cold bending and final heat treatment, in which calibration with compression 3...4%, and after the cutting process with the removal of the surface layer constituting 5...6% of calibrated workpieces, conduct heat treatment to obtain a temporary rupture strengthin=650...730 MPa, relative narrowing=47...55%, relative elongation5=20...35%, and after cold bending before the final heat treatment is carried out by hot bending. The proposed method provides the possibility of implementing a flexible hinge fittings of the type of train wire terminals with a relative radius of bending, representing the ratio of the radius of the TV. 4 Il., table 2.

The invention relates to the field of mechanical engineering and metallurgy and can be used in hardware industry in the manufacture of spring product type train of wire terminals.

A known method of manufacturing a spring products, including steel with a carbon content of 0.52...to 0.60%, silicon 1.5 to 2.0%, manganese...0,9 0,6%, rolling, surface preparation, calibration, heat treatment in the form of patenting, product molding and heat treatment (Ruhstadt A., spring steel and alloys. - M.: metallurgy, 1982, S. 41).

However, the known method does not provide the possibility of manufacturing complex in the form of a spring products from rods of large diameter, for example 13 mm rail rod terminals having a loop in which the relative bending radius flexible representing the ratio of the radius of the edge bending of the stamp to the radius of the workpiece is 1,85 due to the high strength and rigidity of the material, thermally pre-treated by the method patenting. Ultimate strength of steel containing 0.5%, after patenting isin=S+30, where the s - content of coal is Oh steel includes steel grades S-S, rolling, heat treatment, surface preparation, cutting processing, product molding and heat treatment (Zhadan Century. So, Osadchy A. N., Stetsenko N. In. Finishing and heat treatment of rolled. - M.: metallurgy, 1978, S. 28).

However, this known method does not provide the possibility of manufacturing complex-shaped products, such as rail wire spring clips having a loop in which the relative bending radius flexible representing the ratio of the radius of the edge bending of the stamp to the radius of the workpiece is 1,85, because steel with increased carbon content has a low technological plasticity.

The closest analogue of the present invention is a method of manufacturing a spring products, including steel with a carbon content of 0.38...of 0.6%, silicon 1.5 to 2.0%, manganese...0,9 0,6%, rolling, surface preparation, calibration, tool handling, heat treated steel with provision of temporary tear resistancein=1645...2110 MPa relative narrowing=43...51,5%, cold bending of products and their final heat both coinciding with the essential features of the claimed invention: production of predominantly shaped spring steel containing 0,38...0,42% carbon, 1.5 to 1.8% silicon and 0.6...0.8% of manganese, the heat treatment of the rolled billet and/or products, calibration and cutting processing with subsequent cold bending and final heat treatment.

However, the known method does not offer the possibility of manufacturing complex in the form of a spring products, such as rail wire terminals having a loop in which the relative bending radius flexible is of 1.85 or less, because at this level strength steel has a high rigidity, which does not allow to form a loop, or premature destruction due to the formation of cracks.

The basis of the present invention the task is improving the method of manufacturing a spring products, mainly shaped springs, which due to optimization of mechanical properties enables the implementation of flexible hinge fittings of the type of train wire terminals with a relative radius of bending, representing the ratio of the radius of the edge bending of the stamp to the radius zag is, mainly Hosannah springs from steel containing 0,38...0,42% carbon, 1.5 to 1.8 percent, silicon and 0.6...0.8% of manganese, including heat treatment of rolled billets and/or products, calibration and cutting processing with subsequent cold bending and final heat treatment, according to the invention to calibrate with compression 3...4%, and after the cutting process with the removal of the surface layer constituting 5...6% of calibrated workpieces, conduct heat treatment to obtain a temporary rupture strengthin=650...730 MPa, relative narrowing=47...55%, relative elongation5=20...35%, and after cold bending before the final heat treatment is carried out by hot bending.

Manufacturer of spring products, mainly shaped spring steel containing 0,38...0,42% carbon, 1.5 to 1.8% silicon, 0,6...0,8% manganese, is that after rolling consistently conducts pre-heat treated steel with provision of temporary tear resistancein=650...730 MPa relative narrowing=47...55%, relative elongationin=650...730 MPa, relative narrowing=47...55%, relative elongation5=20...35%, the surface preparation prior to cold bending, pre-cold bending, the final hot bending of products and their subsequent final heat treatment.

The lower value of the carbon content of the steel 0,38% selected by providing the necessary hardness in the final heat treated spring products and high quality segments of the workpiece for bending. When the carbon content is less than 0,38% not provided the required hardness of the products and in conjunction with other indicators of quality decreases butt cut blanks appear burrs. The upper value of the carbon content of the steel is 0.42% selected in conjunction with other indicators on the condition of providing technological plasticity of metal for flexible products with a relative radius of bending of 1.85 or less.

Selected in conjunction with other figures is again heat-treated hot-rolled metal ensures the qualitative sections of the blanks.

The upper value ofin=730 MPa pre-calibration and re-created after the cutting processing heat-treated hot-rolled metal in conjunction with other figures provide a more flexible products with a relative radius of bending of 1.85 or less. When values greater than these, there is a fracture of the workpiece or cracks.

Lower values of relative narrowing=47%, and relative elongation5=18% metal, prepared for cold bending of pre-and post-heat treatment in conjunction with other figures, provide more flexible products with a relative radius of bending of 1.85 or less. When a value less than specified, there is a destruction of the workpiece during bending and occur tears.

The upper values of relative narrowing=55% relative elongation5=35% metal, prepared for cold bending, pre-and post-heat treatment in conjunction with other figures provide high-quality segment blanks without burrs. When znenie skimmed the surface layer of the metal during the cutting process, of 5...6% of calibrated steel ensure manufacturability and stability of carrying out the process and guarantee the quality of surface treatment and removal of de-carbonized layer, greatly reducing the elastic properties.

The greatest influence on the conduct of cold bending my limit values of carbon, silicon and manganese in steel and mechanical properties of metal prepared for cold bending. The numerical values of the mechanical properties of hot-rolled metal prior to cold bending after carrying out heat treatment before calibration and after the cutting processing directly affect the conduct of the cold bending, and in conjunction with other figures affect the receipt of a favorable microstructure and size of grain, ensuring manufacturability and stability of the process of preparing steel and cold bending.

In Fig.1 shows a General view of the bar spring terminals; Fig.2 - shows a diagram of the cold flexible bar spring terminals in the region hinges 180where Ru is the radius of the edge bending stamp; R is the radius of the grooved billet of Fig.3 shows the temporal dependence of the rupture strength of the rink; 2 - preliminary heat treatment prior to calibration; 3 - calibration and tool machining; 4 - re-heat treatment after the cutting processing.

An example of the method of manufacturing of spring products, namely wire spring clips of silicon steel containing 0,38...0,42% C, 1.5 to 1.8% of Si, 0,6...0,8% Mn.

Hot rod billet with a diameter of 14 mm of steel with the content of 0.41% C; 1,67% Si; 0,72% Mn in the state of delivery is characterized by the variation of mechanical properties, which falls within the following limits:in=860...1000 MPa,5=11...14%,=26...42%.

After pre-heat treatment - annealing the level and the degree of scatter of mechanical properties of metal corresponds to the following values:in=650...730 MPa,5=20...35%,=47...55%.

Under the influence of calibration and tool handling rod circle 13 mm (R=6.5 mm) mechanical properties of steel vary within the following limits: (in=750...850 MPa,5=14...20%,=33...46%.

Re-heat treatment eliminates poslednee:in=650...730 MPa,5=20...35%,=47...55%.

The mechanical properties of the metal after the second heat treatment are given in table. 1, summary statistics on the mechanical properties are given in table. 2.

Then spent the cold bending of the loop using the bending punch and the radius of the edge bending 12 mm (EN) so that the relative bending radius was 1.85. Then was carried out by hot bending elements to the finished bar spring terminals, then spent the final heat treatment, which consists in hardening and subsequent average vacation.

The metal with the specified level of mechanical properties provides stable cold bending process, the exact execution of the profile geometry and dimensions of the workpiece with high quality cutting ends of the rod without burrs, education in his body the tears and nicks on the surface.

When you increase the time rupture strength heat-treated steelinmore than 750 MPa and the decline of its plasticity - relative elongation 65 less than 20% and a relative narrowing5less than 47% in us.

By reducing the size of the temporary rupture strength less than 650 MPa, the magnitude of the relative elongation of more than 35% and a relative narrowing of more than 55% on the surface of the bar stock after cold bending recorded traces from the machining tool, udevleny and flows, the thickness of which exceeds the permissible limits.

Claims

A method of manufacturing a spring products, mainly shaped spring steel containing 0,38...0,42% carbon, 1.5 to 1.8% silicon and 0.6...0.8% of manganese, including heat treatment of rolled billets and/or products, calibration and cutting processing with subsequent cold bending and final heat treatment, characterized in that prior to calibration with compression 3...4%, and after the cutting process with the removal of the surface layer constituting 5...6% of calibrated workpieces, conduct heat treatment to obtain a temporary rupture strengthIn=650...730 MPa, relative narrowing=47...55%, relative elongation5=20...35%, and after cold Flex

 

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