| Ordinary carbon structural steel | Q195, Q215, Q235 | Good plasticity, can be rolled into steel plates, steel bars, steel pipes, etc. |
| Q225, Q275 | Can be rolled into shaped steel, steel plate, etc. | |
| High quality carbon structural steel | 20#, 45#, etc. | Mainly used to manufacture various machine parts |
| Carbon Tool Steel | T9, T12 etc. | Mainly used to manufacture various props, measuring tools, molds, etc. |
| Cast steel | ZG25 etc. | It is mainly used to manufacture parts with complex shapes and require certain strength, plasticity and toughness, such as gears, couplings, etc. |
| Grade | Level | Chemical composition,% | Deoxygenation method | ||||
| C | Mn | Si | S | P | |||
| No greater than | |||||||
| Q195 | - | 0.06~0.12 | 0.25~0.50 | 0.30 | 0.050 | 0.045 | F、b、Z |
| Q215 | A | 0.09~0.15 | 0.25~0.55 | 0.30 | 0.050 | 0.045 | F、b、Z |
| B | 0.045 | ||||||
| Q235 | A | 0.14~0. 22 | 0.30~0.65 | 0.30 | 0.050 | 0.045 | F、b、Z |
| B | 0.12~0. 20 | 0.30~0.70 | 0.045 | ||||
| C | ≤ 0.18 | 0.35~0.80 | 0.040 | 0.040 | Z | ||
| D | ≤ 0.17 | 0.035 | 0.035 | TZ | |||
| Q255 | A | 0.18~0.28 | 0.40~0.70 | 0.30 | 0.050 | 0.045 | F、b、Z |
| B | 0.045 | ||||||
The final heat treatment methods of medium carbon steel plate include quenching and tempering, low temperature tempering after quenching, low temperature tempering after high frequency quenching, isothermal quenching and medium temperature tempering after quenching.
Quenching and tempering. The organization is tempered sorbite. This structure has good comprehensive mechanical properties, high strength, good plasticity and toughness. The quenched and tempered steel should have good hardenability to ensure uniform structure and performance on the entire section of the quenched and tempered part. Compared with alloy steel, carbon steel has poor hardenability, so it is only suitable for quenching and tempering of medium carbon steel parts with small section size.
Low temperature tempering after quenching. The organization is tempered martensite, which has high strength and appropriate plasticity and toughness.
Low temperature tempering after high frequency quenching. The structure of the high frequency quenching layer is extremely fine hidden needle martensite, and tempered martensite is obtained after low temperature tempering. This treatment can obtain a similar effect to the carburizing treatment. Quenching and tempering or normalizing are generally carried out before high-frequency quenching. Therefore, after high-frequency quenching and tempering, the core of the part has high strength, good plasticity and toughness, and its surface layer has high hardness and good wear resistance. In addition, the surface layer of high-frequency quenched parts produces compressive stress, which has a high fatigue limit and a long service life.
Isothermal quenching. The organization is bainite, which has high strength and good plasticity and toughness.
Temper at medium temperature after quenching. The organization is tempered sorbite.
After proper heat treatment or cold drawing hardening, high carbon steel plate has high strength and hardness, high elastic limit and fatigue limit, and the cutting performance is acceptable, but the welding performance and cold plastic deformation ability are poor. Due to the high carbon content, cracks are prone to occur during water quenching, so double-liquid quenching is mostly used, and oil quenching is mostly used for small-section parts. This type of steel is generally tempered or normalized at medium temperature after quenching or used in a surface quenched state. Mainly used in the manufacture of springs and wear-resistant parts. Carbon tool steel is a high carbon steel that basically does not add alloying elements, and it is also a steel with low cost, good cold and hot workability, and a wide range of use among tool steels. Its carbon content is 0.65 to 1.35%, and it is a steel specially used for making tools. The density of high carbon steel is 7.81g/cm³. Can be used for the production of fishing gear.
Advantage:
High hardness (HRC60-65) and good wear resistance can be obtained after heat treatment.
The hardness is moderate in the annealed state and has good machinability.
The raw materials are easily available and the production cost is low.
Shortcoming:
Poor thermal hardness. When the working temperature of the tool is greater than 200 °C, its hardness and wear resistance drop sharply.
Low hardenability. When water quenching, the diameter of fully hardened is generally only 15-18mm; when oil quenched, the maximum diameter or thickness of fully hardened is only about 6mm, and it is easy to deform and crack.
In order to obtain high hardness and wear resistance of high carbon steel materials, the material itself needs to be heat treated, so it should be annealed before welding before welding.
The weldment should be preheated before welding. The preheating temperature is generally above 250~350℃, and the interlayer temperature must be kept not lower than the preheating temperature during the welding process.
After welding, the weldment must be kept warm and slowly cooled, and immediately sent to the furnace for stress relief heat treatment at 650 °C.
The carbon content of high carbon steel is relatively high, and the weldability is relatively poor. It should be preheated during welding, and should be slowly cooled or tempered at 350 degrees after welding. The specific heat treatment time depends on the thickness of the workpiece. decided. If it is not possible to preheat, it has to be matched with welding materials with good welding performance and good crack resistance, but the welding speed must be reduced.
High carbon steel belongs to the category of poor welding performance. If welding is to be carried out, it should be welded under preheating conditions, and stress relief heat treatment must be carried out after welding.
Flat steel refers to steel with a width of 12-300mm, a thickness of 3-60mm, a rectangular cross-section and a slight blunt edge. Flat steel can be finished steel, and can also be used as blanks for welded pipes and thin slabs for stacked sheets.
Main application: flat steel can be used as a finished material to make hoop iron, tools and mechanical parts, and it can be used as a building frame structure, escalator and so on.
The material of the product adopts the national standard, which is the same as the steel plate. Quality and technical standards are organized according to YB/T4212-2010 standards (Q345B/Q235B refer to GB/T1591-94 and GB/T700-06 standards respectively).
Ganghua Steel can produce medium carbon steel plate, low carbon steel plate, high carbon steel plate, weathering steel plate, wear-resistant steel plate, flat sheet, carbon steel plate, low alloy carbon steel plate, cold rolled/hot rolled carbon steel plate, etc. The factory has a complete production line and experienced technical workers, manufacturing attentively, quality assurance, support for product customization, welcome to contact us!
