What should be paid attention to when bending stainless steel tubing?
Industrial stainless steel tubing has been widely used in various fluid drainage systems, and their good corrosion resistance has become the application in many places with high corrosion resistance.
Due to the use of some corrosive liquids, it is necessary to bend the stainless steel industrial tubing.
What should be paid attention to when bending the stainless steel tubing?
Let me introduce it to you:
Industrial stainless steel tubing
Bending processing of industrial stainless steel tubing is a common processing form in the industry.
It seems simple, but the bending radius of stainless steel industrial tubing needs to be studied and a lot of experience needs to be accumulated.
Because there are many models of stainless steel tubing, some models have ductility and are easy to stretch, while some have high hardness and are easy to crack.
1. Reduced ductility
In order to prevent such cracking in the bending direction, it may be necessary to use a larger bending radius, and when bending in the transverse direction, the reduced ductility can accept a tighter internal bending without damaging the outer surface of the bending.
2. Local heating material
When bending thick materials, it may be necessary to preheat the materials before bending.
After preheating, the bending will be less difficult and require less force.
3. Rebound treatment
The stainless steel tubing will rebound when it is released from the bending force.
The rebound is the release of elastic strain, which is directly related to the material yield strength.
It needs a larger bending angle to reach the required bending angle, especially for the high yield strength stainless steel tubing.
The required angular clearance will increase with the increase of radius. When the radius is relatively large, the rebound amount may be large.
If the bent material is hard, it needs to be processed by heating.
However, in some cases, the heating bending method can only temporarily obtain the required bending angle and radius.
Once the material is cooled, it will rebound slightly.
4. Thermoformed stainless steel tubing
Hot forming of stainless steel tubing can eliminate strain hardening, radius cracking and deformation, and high temperature can change its molecular structure.
Compared with cold forming, the bending machine is easier to handle hot formed stainless steel tubing.
When the stainless steel tubing is heated, it first becomes ductile and then melts.
When it is bent near the melting point, the workpiece will break.
Therefore, hot forming has its limitations.
High temperature may lead to surface oxidation and decarburization, which may cause various problems to the product.
This scheme is generally used cautiously for bending stainless steel tubing.
5. Inner bending radius
For industrial stainless steel tubing, it is necessary to study the value of internal bending radius, and the radius of longitudinal bending needs to be larger than that of transverse bending.
The harder and thicker the stainless steel industrial tubesheet, the larger the bending radius.
There is a skill to determine the bending radius.
Subtract this percentage by 50 according to the material stretching ratio provided by the supplier.
Bending process of 304 stainless steel round pipe
304 stainless steel round pipe is a hollow round stainless steel pipe, which is widely used in various building decoration fields such as fence, stair handrail and courtyard door.
The bending technology is required to be smooth, accurate in angle and free from cracking.
Next, I will explain the bending technology of 304 stainless steel round pipe.
1. Bending method of round pipe
1. Hot bending method:
First, according to the outer diameter of 304 stainless steel round pipe and several rollers of the arc car, fix the rollers on the iron plate, fill the pipe with sand, plug both ends of the pipe with wooden plugs, and heat the bending part with flame before bending.
2. Cold bending method:
It can be formed by rolling several times with a pipe bending machine.
Before using the bending machine, you must do a good job in testing the machine.
There must be a gap of plate thickness at the bottom, and a groove of 8 times the plate thickness must be selected for the bending notch.
2. Technical difficulties
1. During machining, the friction between the workpiece and the tool will generate high heat, and the tool is easy to wear.
Therefore, the requirements for tool materials are more strict, requiring wear resistance and high temperature resistance.
And must meet the requirements of sharp edges.
2. The bending speed is slow, the force is large in the bending process, and the production efficiency is low;
In addition, due to the high heating capacity, sulfur chloride is generally used as a good cooling oil, and the effect is better.
Therefore, workers who process 304 stainless steel round pipes are required to have good experience and technology.
The general requirements for 304 stainless steel round pipe bend R are that the bend radius (center line) R ≥ 1.5 ~ 2 times the diameter.
If the bend R angle is too small, the bend R angle will be flat.
The bending R angle of the same stainless steel pipe is generally consistent to meet the consistency of wheel die.
The straight edge length of the bend must be ≥ 2 times the diameter, otherwise the bend die cannot be clamped smoothly.
2. Process hole:
Process holes shall be reserved for 304 stainless steel round pipe welds to better discharge welding slag generated during welding.
3. Processing performance:
First, pay attention to the processing performance of the lower 304 stainless steel round pipe.
Stainless steel has large plasticity, high toughness, high cutting energy consumption, high cutting temperature, low thermal conductivity of stainless steel, poor heat dissipation and easy to cause tool temperature rise.
Enhance the bonding and weldability of stainless steel, easily block the backlog in the cutting process, and ultimately reduce the surface finish of stainless steel pipes.