The stainless steel sheet is the steel plate with a thickness of less than 3mm. They are widely used in machining parts for automobiles, electrical equipment, and buildings. For example, automobile bodies, electrical equipment structures, and residential reinforcement plates are all made of stainless steel sheets. Regarding shape, some are rolled like coils, and some are flat. Plates with a thickness of 3 to 6mm are called “medium and thick plates” or “medium steel plates”, and plates with a thickness of more than 6mm are called “thick plates” or “thick steel plates.” Thicker steel plates are stronger and can be used in parts for industrial machinery, ships, etc.
Types and uses of stainless steel sheet
stainless steel sheets have a wide range of applications, and there are many types depending on the manufacturing method, etc., and their respective uses also differ.
Hot-rolled stainless steel sheets
Hot rolling is a process that uses rollers to apply pressure to heated metal and perform rolling. The rolling temperature is controlled within a range that does not cause the metal to harden, and it is stretched and extended in a softened state. The processing temperature must be higher than the recrystallization temperature of the metal, such as 900-1200℃ for stainless steel. The advantage of hot rolling is that there is no work hardening and the deformation resistance is small, so the processing performance is better. However, hot rolling also has disadvantages, such as expansion after heating, reduced dimensional accuracy of thin plates, and high manufacturing equipment and energy costs. In addition, heating will form an oxide film on the surface, resulting in a rough appearance. Stainless steel sheets produced by hot rolling can be used in many fields such as construction and industrial machinery.
Cold-rolled stainless steel sheet
Cold rolling is a process carried out at room temperature. Like hot rolling, cold rolling is also a process that uses a metal roll to apply pressure to the metal. Calendering at room temperature will result in work hardening and heat treatment will be applied if necessary to increase its strength. Cold rolling is easy to operate no need for heating equipment. In addition, cold rolling also has the advantages of high dimensional accuracy and small thickness change. There is no oxide film formed on the surface, so the surface of the processed sheet is smooth and clean. On the other hand, it has the disadvantage that it is more difficult to process than hot rolling. Therefore, cold rolling may need to be repeated several times. To make up for the shortcomings of difficult processing, it is sometimes used for roughing with hot rolling and finishing with cold rolling. Cold-rolled stainless steel sheets are commonly used for parts of bicycles, electrical equipment, etc. Cold-rolled stainless steel sheets include SPCC, which has been standardized for circulation. They are also used as a structural material because of their high strength, and stainless steel sheets with a thickness of less than 1mm are sometimes used as elastic materials.
Magnetic stainless steel sheet
Magnetic steel sheet is made by hot rolling and then cold rolled, and last through heat treatment processing. As a soft magnetic material, it can effectively convert into magnetic energy when an electric current passes through it. Magnetic stainless steel sheet contains about 3% silicon in soft steel. The silicon content can be effectively converted into magnetic energy, but too high a silicon content can cause the material to crack. It is mainly used in generators, transformers, and motors by stainless steel sheet manufacturers.
The reasons why the machining process of stainless steel sheet manufacturers is difficult：
Sheets can be processed into complex shapes. Depending on the required specifications, processing may be difficult and require higher processing technology.
The following are three difficult key points that are considered by stainless steel sheet manufacturers to process:
Special machining equipment is required. Sheets can be processed by a variety of processing methods, such as sheet metal processing, stamping, and welding. Each method requires the use of special processing equipment, and the equipment cost is high. In addition, for stamping, a special mold must be made for each part. For parts with complex shapes, multiple molds may be required. When processing the sheets, technical knowledge is very important, such as what accuracy the mold size must reach to ensure the qualified size of the part after processing.
susceptible to heat
Sheets are easily deformed by heat. For example, deformation occurs due to heat during welding or laser processing. Special clamps must be used to hold the material in place, and thermal deformations must be taken into account when setting machining dimensions. In addition, when stainless steel sheet manufacturers measure the dimensions of finished sheets, care must be taken to avoid the effects of thermal expansion and contraction. Especially for large parts with high accuracy requirements, the measurement environment may cause significant changes in dimensions, leading to product detection errors. Care must also be taken during the inspection process to ensure that the temperature and humidity in the measurement room are constant and to allow the workpiece to rest in this environment for some time before measurement.
High precision required
Sheets can also be machined by stainless steel sheet manufacturers for parts that require high precision, such as medical devices. High-precision processing requires appropriate equipment and expertise. For example, choosing sheets that are easy to bend and extrude requires knowledge of materials. For example, if a rolled sheet is used for bending, the bending direction must be consistent with the curling direction to prevent cracking, etc., and the processing requirements need to be indicated on the drawing. To produce high-precision thin sheet parts, the production department and the design department need to jointly study the shape of the parts and the annotation content of the drawings.
The main processing methods for stainless steel sheets
Sheets can be processed into various shapes through cutting, punching, and bending. The main processing methods are as follows:
Welding
Welding is a processing method that connects sheets or pipes and sheets, which requires a high level of skill. Welding between sheets mainly uses laser welding, TIG welding, MAG welding, and spot welding. TIG welding requires a high level of skill because sheets are easily deformed by heat. Laser welding is difficult to deform by heat and can be processed with high precision. Laser welding can also ensure welding strength by setting appropriate output power. It is a processing method that can be used for sheets of various thicknesses.
Blanking
Blanking is a process that cuts or punches holes in the sheets. It is a process that most parts require. In sheet metal processing, turret punch presses and laser cutters are usually used. CO2 laser cutting machines are sometimes used for sheet metal processing, but sheets are easily deformed by heat. Therefore, to reduce deformation, fiber laser cutting machines that are less affected by heat can be used.
Bending
In sheet metal processing, bending is machined by pressure equipment. In stamping, special dies are used to bend metal sheets by applying pressure. The spring back characteristics of the material must be considered in bending. Springback refers to the phenomenon that after bending, when the pressure is removed, the angle will rebound to a certain extent and the shape will recover a little. According to conditions such as thickness, material, and size, the degree of spring back is considered in to design of the mold and process. For example, special dies are made to adjust the size or to perform secondary bending, and punch a groove shape at the root of the bend.
Etching
Etching is a method of processing metal by corroding, which can be processed with high precision. The surface of the sheets is coated with a resist resin for masking, then baked by exposure, and then the surface is developed to expose only the surface that needs to be corroded. Subsequently, the sheet is placed in an etching solution for corrosion treatment, and the pattern to be processed is etched on the thin plate. Finally, the remaining resist is removed and cleaned to complete the entire processing process.
DMTC, as a professional CNC machining manufacturer, has special machining equipment and rich experience for machining stainless steel sheets, such as welding, blanking, bending, and laser cutting processes. If you are looking for machining parts from stainless steel sheets, welcome to send an email to us: susan.yu@szdmtc.com
