Technological manufacturing method of spring steel wire

The manufacturing methods of various spring steel wires are as follows:
Process flow of raw drawing spring steel wire: (steel) wire rod — surface treatment — wire drawing (mattress steel wire can be used in this method) lead quenching spring steel wire: conduct lead bath quenching in the middle specification of wire rod size or cold drawing, and then carry out surface treatment and wire drawing
Galvanized spring steel wire: it is usually hot-dip plated or electroplated in the finished product size, or cold drawn to the specified size after pickling and hot plating

Oil quenched spring steel wire: carbon steel or alloy steel can be used as required. After surface treatment and cold drawing to the finished product size, quenching and tempering treatment is carried out. This process is widely used in steel wire for automobile suspension spring and valve spring, and ordinary spring can also be used

Heat treatment: lead bath quenching process is commonly used for carbon steel spring steel wire, which can obtain very fine pearlite structure (sorbite). It is beneficial to improve deep drawing performance and spring performance. The replacement process of lead bath fluidized bed has not been popularized, and it has been applied in some small diameter steel wires, The purpose of heat treatment of stainless steel wire is to improve the microstructure to meet the needs of drawing

Surface treatment: pickling and phosphating are generally used to remove scale and form phosphating film
Wire drawing: the drawing process of the finished product has a great influence on the product performance. Generally, 90% of the total reduction rate (see area reduction rate) and small pass reduction rate (about 10% – 20%) are used to ensure the toughness of the product. For high strength spring steel wire, the outlet temperature of each pass should be controlled to be lower than 150 ℃. Therefore, good lubrication and sufficient cooling must be provided during drawing, It is helpful to reduce the temperature rise of steel wire by using smaller pass reduction rate and drawing speed

Notes on ordering spring steel wire

Precautions for ordering spring wire.
1. It is clear whether to use raw drawn steel wire or lead quenched steel wire;
2. The requirements of steel wire diameter, strength grade and standard number are put forward;
3. If there are special requirements for strength and diameter tolerance, it shall be put forward;
4. Special packaging and marking requirements;
5. The carbon steel spring is suitable for working under the condition of the maximum long-term temperature of 121 ℃, and the alloy spring steel should be selected as the working temperature.

Production points of spring steel wire

The main processes of spring steel wire production include raw material selection, scale removal, drying, coating treatment, heat treatment, wire drawing, coating treatment, etc.
Removal of scale refers to the removal of oxide scale on the surface of wire rod or intermediate wire blank. The purpose is to prevent the oxide scale from damaging the surface of die and spring steel wire during drawing, prepare good surface conditions for subsequent coating or coating treatment, reduce friction during drawing and reduce drawing force. There are two kinds of methods to remove scale, chemical method and mechanical method. See wire rod chemical descaling and wire rod mechanical descaling.

Improving the sensitivity of automotive spring steel

In order to improve the strength of automobile suspension spring steel, the sensitivity of delayed fracture caused by hydrogen in corrosive environment must be reduced. In Japan, spring steels with different pitting corrosion resistance, namely ordinary spring steel jissup12 and high strength spring steel hds13, and high strength spring steel hds13m series with high pitting corrosion resistance were tested by SSRT in 5mass% NaCl solution. According to the penetration behavior of hydrogen produced by corrosion reaction in steel and SSRT test characteristics, the resistance point was studied The results are as follows.

The hds13m series high strength spring steel added with Ni, Cr, Cu, Mo and B elements which can improve the pitting corrosion resistance is better than that of hds13 spring steel with higher Ni and Mo contents.
The radius and depth of pitting corrosion of spring steel with good pitting corrosion resistance represented by v’cq100 are small, and the deviation is also small.

According to the SSRT test results before and after repeated dry wet corrosion, the higher the v’cq100, the lower the normalized maximum load and fracture time.
According to the results of hydrogen thermal analysis after repeated dry wet corrosion test, abnormal hydrogen peak can be seen in the temperature range of 673 ~ 773k. The results show that the peak value corresponds to the release of hydrogen enriched at the interface between rust layer and steel after corrosion reaction.

With the increase of the amount of hydrogen enriched at the interface, the normalized fracture time will be shortened and the delayed fracture sensitivity will be increased.
By reheating the hydrogen enriched at the interface to more than 673k and releasing it, the increased delayed fracture sensitivity due to repeated dry wet corrosion can be restored.
The addition of alloy elements which can improve the pitting corrosion resistance can reduce the hydrogen generated by repeated dry and wet corrosion and improve the delayed fracture resistance of spring steel.

Use of spring steel wire

The spring should return to its original position after unloading. The smaller the plastic deformation, the better. Therefore, the steel wire should have high elastic limit, yield strength and tensile strength. The higher the yield ratio is, the closer the elastic limit is to the tensile strength, so the higher the strength utilization ratio is, the stronger the spring elasticity is.
The spring absorbs the impact energy by elastic deformation, so the spring steel wire does not have to have high plasticity, but at least it must have the plasticity that can bear the spring forming and enough toughness to bear the impact energy.

Spring usually works under alternating stress for a long time, so it should have high fatigue limit and good creep and relaxation resistance.
Spring used in specific environment, there will be some special requirements for steel wire, for example: the spring used in corrosive medium must have good corrosion resistance.
The instrument should have high sensitivity, low sensitivity and long-term stability. The spring working at high temperature is required to keep enough elastic limit and good creep resistance at high temperature.

In addition, the forming process and heat treatment process of spring steel wire should also be considered. Both cold drawn spring steel wire and oil quenched and tempered spring steel wire are directly wound with steel wire in supply state, and the spring is directly used after stress relief treatment after forming. The tensile strength of cold drawn spring steel wire is slightly higher than that of oil quenched and tempered steel wire.

 

The elasticity of large size cold drawn steel wire is too large, and it is difficult to wind spring. Therefore, the specification of cold drawn spring steel wire is generally less than 8.0 mm, and that of oil quenched and tempered steel wire is generally less than 13.0 mm. In fact, spring steel wire in light drawing state is mostly used for spring with diameter of 13.0 mm, which is cold drawn, wound and then quenched and tempered. Most of the steel wires with diameter above 15.0 mm are made by heating winding process.

Characteristics of die spring

Features of die spring
With the development of die and mold industry, the number and variety of special-shaped section die spring are increasing day by day because of its high rigidity, small volume and long service life. At present, except the square section spring design method is relatively mature, other cross-section spring design methods are mostly based on the specific section, through the test, The so-called empirical design formula derived from the correction coefficient is as follows:
1. The service life of special-shaped steel wire spring is 13-14% longer than that of round section steel wire spring under the same conditions
2. In the same space, the bearing capacity of square cross-section steel wire spring is 43-48% higher than that of round cross-section spring, and the bearing capacity of rectangular spring is more than 50%
3. Special section steel wire spring can produce large deformation and weight
4. The linearity of the spring is better than that of the spring with circular cross-section, that is, the stiffness tends to be constant
5. The range of application is limited by the time when the circular material spring can not reach the required deformation, the design load can not be reached with the circular cross-section material, the spring installation space is small, the replacement of the circular cross-section composite spring, and the place where the spring characteristics are strictly required

Correct use of die spring

In general, the most common causes of mold spring problems are:
It is often due to incorrect selection and use of springs
Spring accounts for a small proportion of the total cost of the mold. Trying to save on the spring may cause premature failure of the spring, increase maintenance costs, reduce productivity, waste more time and labor costs, and even damage the mold and cause greater losses. Therefore, it is a wise investment to ensure that the best mold spring is used in every application

■ correct use concept:
Make sure the type and quantity of spring before constructing the mold, so that the selection of suitable spring becomes the design
Part of the job is the best choice
Let the spring load in advance. For each spring in the installation mold, it is necessary to pre press 5% in order to avoid the load conduction caused by excessive load
The stress is uneven and the spring life is damaged
Do not cut and grind arbitrarily, grind the inner and outer diameter of spring arbitrarily or reduce the number of turns to match the size of die, which will easily damage the spring and cause early failure

The replacement should be carried out at the same time. When repairing, do not replace only one spring, because the spring with different size and length, old and new spring will cause uneven force
Protect and maintain, protect in high temperature, corrosion and other environment, and replace mold spring according to predetermined time interval
When the spring is installed in the renovated mold, the pilot hole should be deepened in proportion to make the spring stable and produce uniform and uniform stress

When the free length of the spring is more than four times of the average diameter, the spring will deform under compression
In this case, sleeve or rod sleeve or both can be used to reduce the possibility of spring bending deformation
The correct service life is long. Although the mold spring design allows the maximum stress, when the mold spring works under the maximum load, it does not
It should be expected to maintain the maximum working life

■ correct installation method:
In order to obtain the best use efficiency, the spring installation should pay attention to the following two points:
1. When it is installed in a flat bottom hole without a guide rod, the depth of the guide hole must be at least the depth of two coils of spring
2. When installed on the guide rod, the length of the guide rod shall be greater than that of the spring

Application and application of die spring

The die spring with rectangular cross section is mainly used for stamping die, metal die casting die, plastic injection mold and mechanical equipment with precise structure. The die spring is mainly made of 50CrVA. It has the characteristics of small installation volume, good elasticity, high rigidity, high precision, rectangular material, color separation spraying (plating) on the surface, and beautiful appearance

 

Advantages and application of disc spring din2093

Advantages of disc spring:
High fatigue life
The later maintenance is simple
Small deformation and high bearing capacity
Economical and safe
A variety of materials and surface treatments are available
Better use, space saving compared to other springs
Single or combined design to achieve the desired load characteristics
Disc spring applications:
Brake
clutch
Wind power equipment
Valve pump industry
Spaceship
Bearing preloading device
More applications of energy storage security system

Disc spring din2093

Disc spring, referred to as disc spring (din2093), is also mistakenly written as butterfly spring. Disc springs was invented and used in the middle of the 19th century. At that time, Belleville, a Frenchman, applied for a design patent for the disc spring. Nowadays, some places still call it Belleville springs.

In the 21st century, disc spring is used in more fields, such as aerospace, defense system, medical equipment, automobile, electric power, construction, machine tool and other industries

The standard of disc spring in the world is the German din2093 standard. Earlier, the disc spring standard used in China was GB / t1972-1992. Now the national standard of disc spring in China is GB / t1972-2005.