Common Stamping Materials- Cold-rolled Sheet

Commonly used Stamping materials include various steel plates, stainless steel plates, aluminum plates, copper plates, and other non-metallic plates

Classification of steel plates (including strip steel):

1. Classification by thickness: (1) Thin plate (2) Medium plate (3) Thick plate (4) Extra thick plate

2. Classification by production method: (1) Hot rolled steel plate (2) Cold rolled steel plate

3. Classification based on surface characteristics: (1) Galvanized sheet (hot dip galvanized sheet, electro galvanized sheet) (2) Tin plated sheet (3) Composite steel plate (4) Color coated steel plate

4. Classification by purpose: (1) Bridge steel plate (2) Boiler steel plate (3) Shipbuilding steel plate (4) Armor steel plate (5) Automotive steel plate (6) Roof steel plate (7) Structural steel plate (8) Electrical steel plate (silicon steel plate) (9) Spring steel plate (10) Others

What we usually refer to as stamped steel plates and sheets refers to thin steel plates (strips); The so-called thin steel plate refers to a steel plate with a thickness of less than 4mm, which is divided into hot-rolled plate and cold-rolled plate.

Hot rolling is the process of using slabs (mainly continuous casting slabs) as raw materials, which are heated and then made into strip steel by roughing and finishing mills. The hot steel strip from the last finishing mill is cooled by laminar flow to the set temperature, and then rolled into steel strip coils by the coiler. The cooled steel strip coil is processed into steel plates, flat coils, and longitudinally cut steel strip products through different finishing lines (leveling, straightening, transverse or longitudinal cutting, inspection, weighing, packaging, and labeling) according to the different needs of users. Simply put, after heating a steel billet (which is the red and hot steel block burned in television), it undergoes several rounds of rolling, edge cutting, and straightening to become a steel plate, which is called hot rolling.

Cold rolling: Hot rolled steel coils are used as raw materials, and after acid washing to remove oxide scales, cold continuous rolling is carried out. The finished product is rolled hard coils. Due to the cold work hardening caused by continuous cold deformation, the strength and hardness of the rolled hard coils increase, and the toughness and plasticity index decrease. Therefore, the stamping performance will deteriorate, and can only be used for parts with simple deformation. Rolling hard coils can be used as raw materials for hot-dip galvanizing plants, as hot-dip galvanizing units are equipped with annealing lines. The weight of the rolled hard coil is generally 6-13.5 tons, and the steel coil is continuously rolled on the hot-rolled pickling coil at room temperature. Due to the lack of annealing treatment, the hardness of the hard rolled plate is very high (HRB greater than 90), and its mechanical processing performance is extremely poor. It can only be subjected to simple directional Bending processing with less than 90 degrees (perpendicular to the coiling direction).

Simply put, cold rolled sheets are processed and rolled on the basis of hot-rolled coils. Generally speaking, it is a processing process such as hot rolling, pickling, and cold rolling.

Due to the fact that cold-rolled plates are processed from hot-rolled plates at room temperature, although rolling can also cause the steel plates to heat up during the processing, people still refer to the steel plates produced by this production process as cold-rolled plates. Due to the continuous cold deformation of hot rolled plates, the mechanical properties of cold rolled plates are relatively poor and their hardness is too high. It is necessary to undergo annealing to restore its mechanical properties, so the cold-rolled plates we usually use have undergone annealing treatment, so the hardness is lower than that of hot-rolled plates, and the toughness is better than that of hot-rolled plates, and the surface quality is much better! Unannealed products are called rolled hard coils, which are generally used to make products that do not require Bending or stretching.

1. Cold rolled sheet

1) Cold rolled ordinary steel sheet

Cold rolled steel sheet is the abbreviation for ordinary carbon structural steel cold rolled sheet, commonly known as cold plate. It is a hot-rolled strip of ordinary carbon structural steel, which is further cold-rolled into a steel plate with a thickness of less than 4mm. Due to the fact that rolling at room temperature does not produce oxide scale, the cold plate has good surface quality and high dimensional accuracy. In addition, annealing treatment results in better mechanical and technological properties than hot-rolled thin steel plates. In many fields, especially in the field of home appliance manufacturing, it has gradually been used to replace hot-rolled thin steel plates.

Applicable grades: Q195, Q215, Q235, Q275;

Symbol: Q-The code for the yield point (limit) of ordinary carbon structural steel, which is the uppercase and lowercase of the first Chinese pinyin letter of "Qu"; 195, 215, 235, 255, 275- numerical values representing their yield point (limit), in megapascals MPa (N/mm2); Due to the comprehensive mechanical properties such as strength, plasticity, toughness, and weldability of Q235 steel, which is among the most common carbon structural steels and can better meet general usage requirements, its application range is very wide.

2) Cold rolled high-quality steel sheet

Like cold-rolled ordinary steel sheets, cold-rolled high-quality carbon structural steel sheets are also the most widely used sheet steel in cold rolling. Cold rolled high-quality carbon steel sheet is made of high-quality carbon structural steel, and is cold-rolled into thin plates with a thickness of less than 4mm.

Applicable grades: 08, 08F, 10, 10F

Symbols: 08, 10- The two digits at the beginning of the steel grade indicate the carbon content of the steel, expressed as the average carbon content × 100 represents; F - Non deoxygenated boiling steel; B - semi killed steel, Z - generally deoxidized killed steel (sometimes without letters).

For example, 08F represents a non deoxidized boiling steel with an average carbon content of 0.08%; Due to the good plasticity and stamping performance of 08F steel plate, it is mostly used to manufacture sheet metal products with generally drawn structures.

Drawing level: Z-deepest drawing level, S-deep drawing level, P-ordinary drawing level

Surface quality: I - Advanced finishing surface, II - Higher finishing surface, III - Ordinary finishing surface

3) Cold rolled steel sheet for deep stamping

Deep drawn cold rolled steel sheets are mostly made of aluminum deoxidized killed steel, which belongs to high-quality carbon structural steel. Due to its excellent plasticity and deep drawing properties, it is widely used in products that require complex structures for deep drawing.

Applicable brand: 08A1

Symbol: The two digits at the beginning of the 08 steel grade indicate the carbon content of the steel, expressed as the average carbon content × 100 represents; A1- Killed steel using aluminum deoxidation.

Surface quality: I - Special advanced finishing surface, II - Advanced finishing surface, III - Higher advanced finishing surface;

Drawing performance level: ZF - Drawable most complex parts, HF - Drawable very complex parts, F - Drawable complex parts.

4) Japanese cold-rolled carbon steel sheet

Applicable grades: SPCC, SPCD, SPCE

Symbols: S-Steel, P-Plate, C-Cold Rolled, Fourth Position C-Common, D-Draw, E-Elongation

Heat treatment status: A - annealed, S - annealed+flat, 8- (1/8) hard, 4- (1/4) hard, 2- (1/2) hard, 1- hard.

Drawing performance level: ZF - used for stamping and drawing the most complex parts, HF - used for stamping and drawing very complex parts, F - used for stamping and drawing complex parts.

Surface processing status: D - Pitted surface (after the roller is processed by a grinding machine and shot blasted), B - Bright surface (after the roller is precision processed by a grinding machine).

Surface quality: FC - Advanced finish surface, FB - Higher finish surface. Status, surface processing status, surface quality code, drawing level (only for SPCE), product specifications and dimensions, appearance accuracy (thickness and/or width, length, unevenness).

5) German cold-rolled carbon steel sheet

Applicable grades: st12, st13, st14, st15, st14-T

Symbols: ST steel, 12 ordinary grade cold rolled steel sheet, 13 stamping grade cold rolled steel sheet, 14 deep drawing grade cold rolled steel sheet, 15 extra deep drawing grade cold rolled steel sheet, and 14-T super cold rolled steel sheet.

Surface quality: FC - Advanced finish surface, FB - Higher finish surface.

Surface structure: b-particularly smooth, g-smooth, m-matte, r-rough.

6) Russian cold-rolled carbon steel sheet

Applicable brand: CT-3k П, 08k П, 08 П C

Symbol: CT ordinary steel, k П- Boiling steel П C-killed steel.

Origin: Russia

7) Approximate comparison of standard steel plate grades between China and the three aforementioned countries (see Table 1)