Now in the market of steel ball mill according to the manufacturing process can be divided into two kinds: casting and forging, but their wear-resisting degree is not the same. Due to the broken material, steel ball need good abrasion resistance and need enough toughness, usually use the material such as alloy steel, high manganese steel, cast iron and chromium iron with a molding forging or casting method, with the corresponding heat treatment process is economic, ball mill ball according to the technology and the material can be divided into:
1, forging steel ball: low carbon steel, medium carbon alloy steel ball, high manganese steel, rare earth chromium molybdenum alloy steel ball;
2, casting steel ball: low chromium cast ball, medium chromium cast, high chromium cast balls.
What kind of steel ball the best in the market now? Now let's analyze:
1. The forging steel ball: good surface quality, good impact resistance, strong toughness, good wear resistance, invulnerability to breakage and loss of circle. Is the metal heating temperature of 1050 ℃ (plus or minus 50 degrees Celsius), pressure of forging machinery for metal blank, make its produce plastic deformation in order to obtain certain mechanical properties, a certain shape and size of forging processing method. Metal forming (forging and stamping) of one of the two part. By forging can eliminate the metal smelting process of as-cast loose defects, such as optimizing the microstructure, at the same time because of the intact metal flow, forging generally better than that of the same material on the mechanical properties of the castings. Related mechanical load is high, the working conditions of severe important parts, in addition to a simpler shape rolling plate, profile or welding parts are available, use forging more. In addition, the forging steel ball to wear must choose the wear-resisting material, such as the national standard of 60 mn, 65 mn, or some company independent research and development of efficient wear-resistant alloy steel material, we adopt national oversize steel production of steel, is also a kind of material, the quality of the steel mill to produce in different range, and forging quality stand or fall of 80% depends on the stand or fall of material, such as high manganese steel, good impact resistance, strong toughness, good wear resistance, not easily broken. Forged steel ball for cheaper price, economic and durable characteristics favored by the masses of users, such as the international mining giant Rio tinto, BHP billiton, anglogold use forged steel ball.
The characteristics of the forging production:
(1) the heated metal forging made into various shapes of tools, machinery parts, or blank of forging. Forging can change internal organization metal materials, granular crystal, improve its mechanical properties.
(2) forging production must use many auxiliary heating equipment, forging equipment and tools.
(3) forging equipment mainly include steam hammer, air hammer, hammer forging hammer, mechanical, plate hammer, hammer, hammer belt spring, crank press, friction press, machine, broaching machine, roll forging machine, etc. Casting steel ball: a, high chrome ball quality indicators: 10.0% or higher chromium content, carbon content between 1.80% and 3.20% are called high chrome ball, national standard requires high chrome ball hardness (HRC) must be more than 58, or impact value ak acuity 3.0 J / ㎝ 2, if this high hardness chromium ball must use high temperature quenching and tempering treatment (the current domestic high chrome ball quenching oil quenching and quenching machine has two quenching way), such as testing hardness (HRC) below 54 shows high chrome ball without quenching process. 2, the chromium ball quality indicators: chromium content 3.0% ~ 7.0%, carbon content between 1.80% and 3.20% are called chrome ball, impact value ak acuity 2.0 J / ㎝ 2, national standard requirements of chromium ball hardness (HRC) must be more than 47, or to ensure the quality of steel ball chromium ball should be used in high temperature tempering treatment (in order to achieve the purpose of eliminating casting stress), such as steel ball surface dark yellow showed that products have been treated with high temperature tempering, such as steel ball surface is metallic color indicates that the product still not high temperature tempering treatment. Three, low chromium ball quality indicators: 0.5% ~ 2.5% chromium content, carbon content between 1.80% and 3.20% are called low chromium ball, national standard requires low chromium ball hardness (HRC) must be more than 45, or impact value ak acuity 1.5 J / ㎝ 2, to ensure the quality of steel ball low chromium ball also need to use high temperature tempering treatment (in order to achieve the purpose of eliminating casting stress), such as steel ball surface dark yellow indicates that the product has been treated with high temperature tempering, such as steel ball surface is metallic color indicates that the product still not high temperature tempering treatment.
