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High manganese steel ball (high manganese steel) refers to alloy steel with manganese content above 10%.
catalogue
I. Classification and introduction of high manganese steel 1. Source of high manganese steel
2. Wear-resistant steel
3. Non-magnetic steel
Second, the casting process and chemical composition of high manganese steel 1
Step 2 charge
3. Melted
4. Loading and molding materials
5, casting process design
6. Heat treatment
7. Cutting and welding
8. Matters needing attention in production
Three. Usage 1. Classification and introduction of high manganese steel 1, the source of high manganese steel
2. Wear-resistant steel
3. Non-magnetic steel
Second, the casting process and chemical composition of high manganese steel 1
Step 2 charge
3. Melted
4. Loading and molding materials
5, casting process design
6. Heat treatment
7. Cutting and welding
8. Matters needing attention in production
Third, use.
Edit this paragraph 1. Classification and introduction of high manganese steel.
1, the source of high manganese steel
1882 obtained the high manganese steel with austenite structure for the first time, and 1883 British hadfield obtained the patent of high manganese steel. High manganese steel can be divided into two categories according to its different uses:
2. Wear-resistant steel
This steel contains manganese 10% ~ 15%, and the carbon content is relatively high, generally 0.90% ~ 1.50%, and most of them are above 1.0%. Its chemical composition is (%): c0.90 ~1.50mn10.0 ~15.0si0.30 ~1.05p ≤ 0.10. It is the most widely used high manganese steel and is often used in the production of high manganese steel. The as-cast structure of high manganese steel with the above composition is usually composed of austenite, carbide and pearlite, and sometimes contains a small amount of phosphorus crystals. When the amount of carbide is large, it often appears on the grain boundary in the form of a network. Therefore, high manganese steel with as-cast structure is brittle and cannot be used, so it needs solution treatment. The common heat treatment method is solution treatment, that is, the steel is heated to1050 ~1100℃, and the as-cast structure is eliminated by heat preservation to obtain single-phase austenite structure, and then quenched with water to keep this structure at room temperature. After heat treatment, the strength, plasticity and toughness of steel have been greatly improved, so this heat treatment method is often called water toughening treatment. The mechanical properties after heat treatment are σ B615 ~1275mpa σ 0.2340 ~ 470mpa ζ15% ~ 85% ψ15% ~ 45% akl96 ~ 294j/cm2 hb. When high manganese steel with austenite structure is subjected to impact load, the metal surface is plastically deformed. The result of deformation strengthening is that there is obvious work hardening phenomenon in the deformed layer, and the surface hardness is greatly improved. It can reach HB 300 ~ 400 under low impact load and HB 500 ~ 800 under high impact load. Under different impact loads, the depth of hardened layer can reach 10 ~ 20 mm, and the hardened layer has high hardness and can resist impact abrasive wear. High manganese steel has excellent wear resistance under the condition of strong impact abrasive wear, so it is often used to make wear-resistant parts in mining, building materials, thermal power and other mechanical equipment. Under the condition of low impact, because the work hardening effect is not obvious, high manganese steel can not give full play to the characteristics of the material. The brand and application range of high manganese steel commonly used in China are: ZGMN13-1(C1.10% ~1.50%), Using ZGMN13-2 (C1.00) ZGMN13-3 (C 0.90% ~1.30%), the manganese content of the above four steels is1/Kloc-0. In the process of cold deformation under impact load, steel is strengthened due to the large increase of dislocation density, dislocation transmission, dislocation plugging and the interaction between dislocation and solute atoms. This is an important reason for work hardening. Another important reason is that the stacking fault energy of high manganese austenite is low, which is easy to occur during deformation, thus creating conditions for the formation of ε martensite and deformation twins. In the deformation hardening layer of high manganese steel with conventional composition, high density dislocation, dislocation plugging and entanglement can often be seen. The appearance of ε martensite and deformation twins makes it difficult for steel to deform, especially the latter. All the above factors have greatly strengthened the hardened layer of high manganese steel and greatly improved its hardness. High manganese steel is very easy to work and harden, so it is difficult to work. Most of them are castings, and a few are forged. The castability of high manganese steel is better. The melting point of steel is low (about 1400℃), the temperature range between liquid phase and solid phase of steel is small (about 50℃), the thermal conductivity of steel is low, the fluidity of molten steel is good, and it is easy to cast. The linear expansion coefficient of high manganese steel is 1.5 times that of pure iron and twice that of carbon steel, so the volume shrinkage and linear shrinkage are large during casting, and stress and cracks are easy to appear. In order to improve the properties of high manganese steel, many studies have been carried out in alloying, microalloying, carbon and manganese content adjustment and precipitation strengthening treatment, and they have been applied in production practice. The appearance of metastable austenitic manganese steel, compared with local high, can greatly reduce the content of carbon and manganese in steel and improve the deformation strengthening speed of steel, which is suitable for high, medium and low impact loads and is a new development of high manganese steel.
3. Non-magnetic steel
The manganese content of this steel is more than 17%, and the carbon content is generally lower than 1.0%, which is often used to manufacture retaining rings in automobile industry. The density of this steel is 7.87 ~ 7.98g/cm3. Due to the high content of carbon and manganese, the thermal conductivity of steel is poor. The thermal conductivity is12.979 w/(m℃), which is about 1/3 of that of carbon steel. Because steel is austenitic and nonmagnetic, its magnetic permeability μ is 1.003 ~ 1.03 (h/m).
Edit this paragraph II. Casting technology of high manganese steel.
Under the working conditions of high energy impact, high manganese steel and ultra-high manganese steel castings have a wide range of applications. Many foundries lack the necessary knowledge about producing this kind of steel castings. The specific operation is briefly described for the reference of producers.
1, chemical composition
High manganese steel is divided into five grades according to national standards, the main difference is carbon content, ranging from 0.75% to 1.45%. Great influence and low carbon content. The manganese content is between11.0%-14.0%, and generally should not be lower than 13%. There is no national standard for ultra-high manganese steel, but the manganese content should be greater than 18%. Silicon content has a great influence on impact toughness, so the lower limit should be taken, and it is appropriate to not exceed 0.5%. Low phosphorus and sulfur is the most basic requirement. Because high manganese content naturally plays a role in desulfurization, reducing phosphorus is the most important thing, and try to reduce phosphorus below 0.07%. Chromium can improve the wear resistance, generally around 2.0%.