Heat treatment process of 40crnimova torsion bar spring

What is the heat treatment process of 40crnimova torsion bar spring?

The manufacturing process route of torsion bar spring: cutting → upsetting → annealing → end processing → quenching → tempering → shot peening → strong torsion treatment → inspection → antirust treatment.

The heat treatment process of 40crnimova torsion bar spring is quenching and tempering treatment (quenching and tempering torsion bar), the quenching diameter is 70mm, the tensile strength after quenching and tempering is 1500 ~ 1700mpa, the quenching heating temperature is 830 ~ 890 ℃ oil quenching. If the low hardness 415 ~ 495hbs (i.e. the working stress reaches 735 ~ 882mpa), the tempering temperature is about 500 ℃; if the high hardness is 47 ~ 52hrc (i.e. the working stress is 883 ~ 932mpa), the tempering temperature is about 400 ℃.

Attention should be paid in heat treatment: surface oxidation and decarburization shall be prevented during quenching and heating, and overheating shall not occur. Tempering shall be timely and sufficient.

Various spring terms

Serial number / Chinese name / English name / relevant explanation
09.0820 spring is an elastic element which makes use of the elastic and structural characteristics of materials to keep the specified relationship between deformation and load;
09.0821 helical spring: spiral spring;
09.0822 cylindrical spiral spring, cylindrical spiral spring;
09.0823 cylindrical helical compression spring: cylindrical helical compression spring under compression force;
09.0824 cylindrical spiral tension spring the cylindrical spiral spring with tensile force;
09.0825 cylindrical helical torsion spring; cylindrical helical torsion spring;
09.0826 variable pitch cylindrical helical spring with unequal pitch;
09.0827 multi strand spiral spring the cylindrical coil spring is made by twisting multiple strands of steel wire into steel cable;
09.0828 middle convex spiral spring the coil diameter decreases to both ends;
09.0829 medium concave spiral spring hourglass shaped spring the coil diameter increases to both ends;
09.0830 tightly coiled helical spring is a kind of spiral spring which is pressed along the axial direction of the spring during cold rolling forming;
09.0831 truncated cone spiral spring;
09.0832 truncated cone scroll spring is made of truncated cone spiral spring made of material;
09.0833 plane scroll spring spiral spring in one plane
09.0834 Belleville spring has a disc-shaped spring outline;
09.0835 disc shaped spring the combination spring is composed of multiple disc springs, or a combination of several groups of disc springs;
09.0836 ring spring is composed of a number of three elastic rings with inner and outer conical surfaces;
09.0837 leaf spring a spring made of single or multiple plates (spring plate);
09.0838 spring hoop buckle fastening the metal hoop of spring plate;
09.0839 semi elliptic leaf spring with bow shaped outline;
09.0840 constant stiffness semi elliptic spring with constant stiffness;
09.0841 variable rate semi elliptic spring with variable rate semi elliptic spring;
09.0842 the full elliptic spring has elliptical outline;
09.0843 constant rate full elastic spring
09.0844 variable rate full elliptic spring the elliptical plate spring with variable stiffness changes during operation;
09.0845 the cantilever leaf spring is a cantilever leaf spring;
09.0846 combined spring a combination of multiple or multiple springs;
09.0847 torsion bar spring;
09.0848 serpentine spring is a serpentine spring;
09.0849 wire spring a spring of special shape made of wire (or wire);
09.0850 flat spring various sheet springs made of strip or plate;
09.0851 rubber spring rubber spring is a kind of spring which has the function of buffering and damping;
09.0852 compression type rubber spring;
09.0853 shear type rubber spring;
09.0854 torsion type rubber spring;
09.0855 combined type rubber spring is composed of several simple rubber components;
09.0856 laminated rubber spring a rubber spring made of several rubber pads laminated with metal diaphragms
09.0857 sleeve shape rubber spring the rubber spring is composed of rubber sleeve and inner and outer steel sleeve;
09.0858 rubber stop is a rubber element which can limit the movement of the body and act as a buffer;
09.0859 air spring the air spring is filled with compressed air in a retractable closed container

Mechanical and electrical technical requirements

1. Remove oxide scale of parts.
2. There should be no scratch, scratch and other defects on the surface of parts.
3. Remove burr and flash.
4. After quenching and tempering, HRC50 ~ 55.
5. High frequency quenching, tempering at 350-370 ℃, hrc40-45.
6. Carburizing depth is 0.3mm.
7. High temperature aging treatment.
8. Undeclared shape tolerance shall meet the requirements of gb1184-80.
9. The allowable deviation of unmarked length is ± 0.5mm.
10. The tolerance zone of casting is symmetrical to the basic dimension configuration of blank casting.
11. The fillet radius R5 is not noted.
12. The undeclared chamfer is 2 × 45 °.
13. Blunt the acute angle.
14. All seals must be soaked in oil before assembly.
15. It is allowed to heat the rolling bearing with oil, and the oil temperature shall not exceed 100 ℃.
20. After the gear is assembled, the contact spot and side clearance of the tooth surface shall comply with the provisions of GB10095 and gb11365.
21. When assembling the hydraulic system, it is allowed to use sealing filler or sealant, but it should be prevented from entering the system.
22. The parts and components (including purchased parts and outsourcing parts) entering the assembly must have the certificate of inspection department before they can be assembled.
23. The parts must be cleaned and cleaned before assembly, without burr, flash, oxide scale, rust, chip, oil stain, colorant and dust.
24. Before assembly, the main matching dimensions of parts and components, especially the interference fit size and relevant accuracy shall be rechecked.
25. Parts are not allowed to knock, bump, scratch and rust during assembly.
26. When the screws, bolts and nuts are tightened, it is strictly forbidden to hit or use improper screwdrivers and spanners. After fastening, the screw groove, nut, screw and bolt head shall not be damaged.
27. The fasteners with specified tightening torque requirements must use torque wrench and be tightened according to the specified tightening torque.
28. When the same part is fastened with multiple screws (bolts), the screws (bolts) shall be tightened alternately, symmetrically, gradually and evenly.
29. The taper pin shall be painted with the hole during assembly, and its contact rate shall not be less than 60% of the matching length, and shall be evenly distributed.
30. The flat key and the two sides of the keyway on the shaft shall be in uniform contact, and there shall be no gap on the mating surface.
31. The number of tooth surfaces contacted at the same time by spline assembly shall not be less than 2 / 3, and the contact rate shall not be less than 50% along the length and height of key teeth.
32. After the sliding fit flat key (or spline) is assembled, the parts can move freely without uneven tightness.
33. Excess adhesive should be removed after bonding.
34. The semicircular hole of bearing outer ring, open bearing seat and bearing cover shall not be stuck.
35. The outer ring of the bearing shall be in good contact with the semicircular hole of the open bearing seat and the bearing cover. During the color coating inspection, the bearing cup shall be in the range of 120 ° symmetrical to the center line of the bearing seat and 90 ° to the center line of the bearing cover
Uniform contact within the enclosure. When the feeler gauge is used for inspection within the above range, the 0.03mm feeler gauge shall not be inserted into 1 / 3 of the outer ring width.
36. After assembly, the bearing outer ring should be in even contact with the end face of the locating end bearing cover.
37. After the rolling bearing is installed, it should rotate flexibly and stably by hand.
38. The joint surface of the upper and lower bearing shells should be close to each other and cannot be checked with a 0.05mm feeler gauge.
39. When fixing bearing bush with locating pin, reaming and pin distribution shall be carried out under the condition that the bearing mouth surface and end face are level with the opening and closing surface and end face package of relevant bearing holes. The pin shall not be loose after being driven in.
40. The bearing body and bearing seat of spherical bearing shall be in uniform contact, and the contact shall not be less than 70% by color coating method.
41. When the surface of alloy bearing liner is yellow, it is not allowed to use, and there is no nucleation phenomenon within the specified contact angle. The area outside the contact angle shall not be greater than 10% of the total area of non-contact area.
42. The reference end face of the gear (worm gear) should fit with the shaft shoulder (or the end face of the locating sleeve), and can not be checked with a 0.05mm feeler gauge. The perpendicularity requirements between the gear reference end face and the axis shall be ensured.
43. The joint surface of gearbox and cover shall be in good contact.
44. Before assembly, strictly check and remove the sharp corners, burrs and foreign matters left in the machining of parts. Ensure that the seal will not be scratched during installation.
45. No cold shut, crack, shrinkage cavity, penetrating defect and serious defect (such as under casting, mechanical damage, etc.) are allowed on the casting surface.
46. The casting shall be cleaned up without burr and flash, and the riser on the non machining indication shall be cleaned and flush with the casting surface.
47. The cast characters and marks on the non machined surface of the casting shall be clear and distinguishable, and the position and font shall meet the requirements of the drawing.
48. The roughness of non machined surface of casting, sand casting R, shall not be greater than 50 μ M.
49. The casting riser and flying thorn should be removed. The residual amount of pouring and riser on the non machined surface should be leveled and polished to meet the surface quality requirements.
50. The molding sand, core sand and core bone on the casting shall be removed.
51. The casting parts with inclination should be symmetrically arranged along the inclined plane.
52. The molding sand, core sand, core bone, fleshy and sticky sand on the casting shall be grinded and cleaned up.
53. The dislocation and boss casting deviation should be corrected to achieve a smooth transition and ensure the appearance quality.
54. The wrinkle on the non machined surface of the casting shall be less than 2 mm in depth and more than 100 mm in spacing.
55. The non machined surfaces of machine castings need shot peening or roller treatment to meet the requirements of cleanliness grade Sa21 / 2.
56. Castings must be water toughened.
57. The surface of the casting should be flat, and the gate, burr and sticking sand should be removed.
58. Casting defects such as cold shut, crack and hole which are harmful to use are not allowed.
59. Rust, oxide scale, grease, dust, soil, salt and dirt must be removed from the surface of all steel products to be coated before painting.

Rectangular spring surface treatment technology affects the overall performance of the mold

The current mold is the main process equipment for industrial production. The development of modern industrial products and the improvement of technical level largely depend on the development level of the mold industry.

The current mold is the main process equipment for industrial production. The development of modern industrial products and the improvement of technical level largely depend on the development level of the mold industry. Since the Second World War, the increase in automation has led to rapid development of foreign molds. Although my country is a big country in mold production, it is not a strong country in mold manufacturing. For springs that match the mold, this detail is also the key to achieving quality. Affect the performance of the entire mold.

The surface of the spring is identified by various paint layers. For example, light and small loads are represented by yellow paint; light loads are represented by blue paint; medium loads are represented by red paint; extremely heavy loads are represented by brown paint;

Performance analysis: A good paint layer to match the spring surface treatment can be described as two birds with one stone. The color is used to identify various technical parameters, which is convenient for industrial production and operation, and the anticorrosion performance of the spring surface can be better guaranteed.

At present, the main manufacturers that have successfully used the above methods are many foreign manufacturers, such as Japan Dongfa Company.

In China, only a small number of manufacturers have effectively visited. At present, it is mainly due to some fixed technical requirements, such as the use of imported materials to achieve foreign standards, but there is an obvious gap in the surface treatment effect of the entire spring.

Manual paint spraying is generally used in China, and the appearance will appear sagging, leaking, poor combination, and poor rust resistance. Due to its own process limitations, a large number of products have to be stripped and reworked.

The electrophoretic paint is used abroad. In the water-soluble paint tank, the workpiece is used as the cathode, and a certain voltage and time are applied to form a paint layer of uniform thickness on all surfaces of the spring, and then it can be cleaned and dried. The appearance is clean and bright, no particles, no bottoming phenomenon, good binding force, not easy to fall off, good hardness is 3-4H, if the British LVH company polyurethane cathode electrophoretic paint is used, its flexibility is quite good.

There is no strong solvent smell in the operating environment, less air pollution, and the wastewater treatment and discharge process is simple. Just adjust the resin of the PH sedimentation electrophoresis paint, and then discharge clean water.

The design process for a domestic manufacturer is: forming spring → shot peening → hanging tool → alkaline degreasing → double water washing → (micro acid 1% neutralization) phosphating → double water washing → double deionized water washing → cathode system polyurethane color Electrophoretic paint→Recycling→Double water washing→Assisting washing→Baking and curing→Under hanging tool.

Lubrication is necessary in metal stamping

In the stamping process of general workpieces, the temperature will rise rapidly in the stamping process, especially in the process of cold forging and stamping. If the workpiece is pressed directly without lubrication, the service life of the die will be shortened and the precision will be reduced. Therefore, a lot of cost will be invested in the improvement of the die. Because of this reason, it is necessary to press lubrication in cold forging.


When tens or hundreds of stamping parts are produced per minute, the processes of feeding, stamping, discharging and scraping are completed in a short time, which often leads to personal, equipment and quality accidents. Therefore, the safety production in stamping is a very important problem. The safety measures for stamping are as follows:

① Realize mechanization and automation in and out of materials. ② Set up mechanical protection device to prevent hand injury. Application of mold shield, automatic material return device and manual tools in and out of the material. ③ Set up electrical protection and power-off devices. Photoelectric or air curtain protection switch, double or multi hand series start switch, anti misoperation device, etc. ④ The structure of the clutch and brake is improved. After the danger signal is sent, the crankshaft, connecting rod and punch of the press can stop at the original position immediately.

Strength solutions for metal stamping

In the past, in the production of deep drawing or re punching parts, everyone thought that pressure resistant (EP) lubricating oil was the best choice to protect the mold. Sulfur and chlorine EP additives have been mixed into pure oil to improve mold life for a long time. However, with the emergence of new metal high strength steel and strict environmental protection requirements, the value of EP oil-based lubricating oil has decreased or even lost its market.

EP oil-based lubricants lose their properties during the forming of high-strength steel at high temperature, and cannot provide physical mold protection diaphragm in extreme temperature applications. The extreme temperature irmco high solid polymer lubricant can provide necessary protection. With the deformation of metal in the stamping die and the increasing temperature, EP oil-based lubricating oil will become thinner, and in some cases it will reach flash point or burn (smoke).


The consistency of irmco water-based stamping lubricants is generally much lower at the beginning of spraying. As the temperature rises during the forming process, it becomes thicker and stronger. In fact, polymer extreme temperature lubricants are “heat seeking” and stick to the metal, forming a diaphragm that can reduce friction. This protective barrier allows the workpiece to extend without cracking and bonding when the most demanding part is formed, thus controlling friction and metal flow. It can effectively protect the die, prolong the service life of the die and improve the stamping strength.

Problems in metal stamping

1. Mold problems
The die used in stamping process is usually special. Sometimes a complex part needs several sets of dies to process and form. The die manufacturing has high precision and high technical requirements, which is a technology intensive product. Therefore, only in the case of a large number of stamping parts, the advantages of stamping can be fully reflected, so as to obtain better economic benefits.

2. Security issues
There are also some problems and shortcomings in stamping process. It is mainly manifested in two kinds of public hazards, noise and vibration, and the safety accidents of operators occur from time to time. However, these problems are not entirely due to the stamping process and die itself, but mainly due to the traditional stamping equipment and backward manual operation. With the progress of science and technology, especially the development of computer technology, with the progress of mechatronics technology, these problems will be solved as soon as possible.

3. High strength steel stamping
Nowadays, high-strength steel and ultra-high-strength steel have realized the lightweight of vehicles and improved the collision strength and safety performance of vehicles, so they have become an important development direction of vehicle steel. However, with the improvement of sheet metal strength, the traditional cold stamping process is prone to crack in the forming process, which can not meet the processing requirements of high strength steel plate. In the case that the forming conditions can not be met, the hot stamping forming technology of ultra-high strength steel sheet is gradually studied in the world. This technology is a new technology which integrates forming, heat transfer and phase transformation.


It is mainly based on the characteristics of sheet metal plasticity increasing and yield strength decreasing under high temperature austenite state. However, hot forming needs deep research on process conditions, metal phase transformation and CAE analysis technology. At present, this technology is monopolized by foreign manufacturers and its development is slow in China.

4j52 alloy steel

In 4j52 alloy steel, the combined gold is stable austenite structure. The alloy is easy to be cold and hot worked. Hot working temperature should not be too high, heating time should not be too long, should avoid heating in sulfur-containing atmosphere.

Fe Ni fixed expansion alloys are a series of fixed expansion alloys which can match soft glass and ceramics with different expansion coefficients in a given temperature range by adjusting the nickel content. The expansion coefficient and Curie point increase with the increase of nickel content. These alloys are widely used as sealing structural materials in electric vacuum industry.

Organizational structure of 4j52:
1. 4j52 phase transition temperature
2. Time temperature microstructure transition curve of 4j52
3. Microstructure of 4j52 alloy: the combined gold is stable austenite structure.
4. Grain size of 4j52: the grain size of alloy deep drawing belt shall not be less than Grade 7, and the grain size less than Grade 7 shall not exceed 10% of the area. When the average grain size of the strip with thickness less than 0.13MM is estimated, the number of grains along the thickness direction of the strip shall not be less than 8.

4J52 alloy

Fe Ni fixed expansion alloy is a series of constant expansion alloys which can match soft glass and ceramics with different expansion coefficient in a given temperature range by adjusting nickel content. Its expansion coefficient and Curie point increase with the increase of nickel content

The heat treatment system of expansion coefficient performance test sample specified in the standard is: heating to 850 ℃± 20 ℃ in protective atmosphere or vacuum, holding for 1h, cooling to below 400 ℃ at the speed of no more than 300 ℃ / min.
Specification and supply status of 4j52
The varieties are bar, tube, plate, strip and wire.
Melting and casting process of 4j52
Smelting in non vacuum induction furnace, vacuum induction furnace or electric arc furnace.
Application and special requirements of 4j52
4j52 is a typical brand of glass sealing alloy. It has been used in aviation factory for a long time with stable performance.
4j52 alloy is mainly used for sealing with soft lead glass, small electronic tube lead.

In application, the selected sealing material should match the expansion coefficient of the alloy. The grain size should be controlled during heat treatment to ensure good deep drawing properties. When forging and rolling materials are used, the air tightness of materials shall be strictly inspected.

Scope of machining and commonly used instruments

Scope of machining
1. Processing of various metal parts;
2. Sheet metal, box, metal structure;
3. Mechanical processing of titanium alloy, high temperature alloy, non-metal, etc.;
4. Design and manufacture of wind tunnel combustion chamber;
5. Design and manufacture of non-standard equipment.
6. Mold design and manufacture.

And common equipment
The machinery required for processing includes digital display milling machine, digital display molding grinder, digital display lathe, electric discharge machine, universal grinding machine, machining center, laser welding, medium wire walking, fast wire walking, slow wire walking, cylindrical grinding machine, internal grinding machine, Precision lathes, etc., can process precision parts such as turning, milling, planing, and grinding. These machines are good at turning, milling, planing, and grinding of precision parts. They can process various irregular shaped parts with a processing accuracy of up to 2 μm. .