1. Processing Technology of Stainless Steel in Range Hood
According to the stainless steel manufacturing method, it is divided into hot rolled cold rolled
Cutting and punching
Since stainless steel is stronger than general materials, it requires higher pressure during stamping and cutting.
When the gap between the knife and the knife is accurate, poor shearing and work hardening will not occur, and it is best to use plasma
Laser or laser cutting. When gas cutting or arc cutting has to be used, the heat-affected zone should be researched.
Grinding and necessary heat treatment.
Basic principles of design: (Note: all data only applies to stainless steel)
- 1. The shape and inner hole of the blanking parts should avoid sharp corners, and generally add the arc radius R≥0.5t, (t is the thickness of the material, the same below);
- 2. Round holes are preferred for punching. The minimum size of punching is the diameter of round hole>1.3t, the width of the short side of rectangular hole>1.0t;
- 3. The minimum distance between the punching edge of the part and the shape: >t when the shape is not parallel to the adjacent hole or edge, and >1.5t when it is parallel;
2. Stretching
It is easy to generate frictional heat, so use stainless steel with high-pressure resistance and heat resistance at the same time after the completion of the molding process
The oil attached to the surface should be removed.
Basic principles of design:
- 1. Between the bottom of the stretched part and the straight wall
Fillet radius size requirements, t<r1=(
3~5)t ≤8t (t is the material thickness, the same as below);
- 2. The rounded corners between the flange and the wall of the stretched part
Radius size requirements:
2t<r2=(5~8)t ≤8t;
- 3. The diameter of the inner cavity of the circular drawing piece should be taken
D ≥d+10t, to compress
The board will not be wrinkled when pressed tightly.
- 4. The rounded corners between two adjacent walls of the rectangular stretched part
The radius should be r3 ≥3t, to reduce the tension
The number of extensions should be as far as possible to take r3 ≥H/5,
In order to pull it out at once;
- 5. When a round non-flange stretched part is formed at one time
, H/d ≤0.4.
3. Bending processing
The thin plate can be bent to 180, but to reduce the cracks on the curved surface, it is best to be 2 times the thickness of the plate with the same radius.
When the thick plate is along the rolling direction, the radius of 2 times the thickness of the plate is given, and the radius of 4 times the thickness of the plate when bent in the direction perpendicular to the rolling is
It is necessary, especially when welding, to polish the surface of the welding area to prevent processing cracks.
Basic principles of design:
- 1. In general, the minimum straight edge height requirement, h>2t;
- 2. The minimum bending inner radius is 2.0t;
- 3. The resilience of bent parts is currently mainly regulated by the manufacturer during mold design.
Avoiding and suppressing the reinforcing ribs in the bending zone can not only improve the rigidity of the workpiece but also help restrain the spring back.
4. Flanging and Tapping
Mostly used in the processing of stainless steel pipes
Flanging and tapping tools melt drill and hot drill (Frictiondrill), to realize a new revolution in thin sheet and pipe processing
5. Connection Method of Stainless Steel
- Riveting welding: When assembling stainless steel parts, compulsory assembly should be avoided, especially flame-roasting assembly should be avoided. If plasma cutting is used temporarily during the assembly or production process, isolation measures should be taken to avoid contamination of other stainless steel parts by cutting slag. After cutting, the cutting residue on the workpiece should be cleaned up.
- Welding: Before welding stainless steel parts, oil, rust, dust, and other debris must be carefully removed. When welding, use argon arc welding as much as possible. When using manual arc welding, use small current and fast welding to avoid swinging. It is strictly forbidden to ignite the arc in the non-welded area, and the ground wire is located in an appropriate position and connected firmly to avoid arc scratches. Anti-spatter measures (such as white ash, etc.) should be taken during welding. After welding, use a stainless steel (no carbon steel) flat shovel to thoroughly clean the slag and spatter.
- Multi-layer welding: During multi-layer welding, the slag between layers must be removed. When multi-layer welding, the temperature between layers should be controlled, generally not exceeding 60℃.
- Welding seam: Welding seam joints should be ground. The surface of the welding seam shall not have defects such as slag, pores, undercut, spatter, cracks, lack of fusion, incomplete penetration, etc. The welding seam and base metal shall be smoothly transitioned and shall not be lower than the base material.
Surface Treatment
Commonly used stainless steel surface treatment techniques have the following treatment methods:
- 1. Whitening treatment of the natural color of the surface
- 2. Mirror bright treatment on the surface
- 3. Surface coloring treatment
- 4. Surface drawing treatment
Applications: Chemical, Food, Medicine, Papermaking, Petroleum, Atomic Energy Industry
Construction, kitchenware, tableware, vehicles, various parts
6. Economic Cost
The price of national standard stainless steel products is about 20,000 yuan per ton.
The price per ton for the national standard 7075 aluminum alloy is about 16,000 yuan.
The tensile strengths of the two materials are:
National standard stainless steel 530-620MPa,
National standard 7075 aluminum alloy 540-560MPa.