The difference between forged steel ball and casting steel ball
Now in the market according to the manufacturing process of steel ball of the ball mill can be divided into two kinds:
Degree of wear-resistant casting and forging， but they are not the same. Due to the broken materials， steel ball need good abrasion resistance and toughness enough， usually use the material such as alloy steel， high manganese steel， cast iron and chromium iron with a forming， forging or casting method with the corresponding heat treatment process is economic， ball mill ball according to the process and material can be divided into:
1， forging steel ball: low carbon alloy steel balls， middle carbon alloy steel， high manganese steel ball， 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 is best in the market now? Now let's analyze:
1. Forging steel ball surface quality is good， good impact resistance， strong toughness， good wear resistance， not easy broken and lost. Is the metal heating temperature of 1050 ℃ (plus or minus 50 degrees)， pressure of forging machinery for metal blank， make its produce plastic deformation in order to obtain certain mechanical properties， a certain shape and size 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 osteoporosis， optimization， the microstructure at the same time as the intact metal flow， forging generally superior to the same material on the mechanical properties of the castings. Related mechanical load is high， the working conditions in the severe important parts， in addition to the shape of a simple rolling sheet， profiles are available or welding parts， use forging more. In addition， the forging steel ball to wear must choose the wear-resistant materials， such as the national standard of 60 mn， 65 mn， or some of the company independent research and development high wear-resisting alloy steel material， and recommended national oversize steel mills production， is also a kind of material， in different steel mill to produce quality also differ， 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 easy broken. Forged steel ball for cheaper price， economic and durable characteristics favored by the masses of users， such as the international mining giantRiotinto， BHP billiton， anglogold use forged steel ball.
The characteristics of the forging production:
(1) after the heating of forging metal materials made from a variety of tools， machinery parts， or in the shape of blank， of forging. Forging can change internal organization metal materials， refining crystal， improve its mechanical properties. (2) forging production must use the heating equipment， forging equipment and many auxiliary tool. (3) forging equipment mainly include steam hammer， air hammer and forging hammer， hammer machine， plate hammer， spring hammer and belt hammer， friction press， hydraulic press， crank press forging machine， broaching machine， roller， etc.
2. The casting steel ball: low chromium cast ball wear-resisting performance is poor， broken rate is high， although cheap， but the comprehensive performance to price ratio is not high， in this is not recommended. High chromium cast ball hardness is good， is a high-quality wear-resistant material， in cement industry in the field of dry type ball mill is widely used， but the high chrome casting balls toughness is bad， in the ball mill is greater than 3 meters in diameter are prone to breakage， and the price is higher.
The influence of casting steel ball material: generally speaking， the greater the hardness of the steel ball its abrasion resistance is large. To improve the wear resistance of steel ball， we should increase the hardness， but with the increase of hardness， shock toughness of steel ball will be reduced， the hardness of steel ball at the same time with material and hardness of the plate， not too high (smashed the plate)， also shoulds not be too low (not wear). Therefore， how to balance ball suitable hardness and good resistance to impact toughness is the key to improve the abrasion resistance of steel ball.
Steel ball commonly used materials: low carbon alloy， high manganese steel， high carbon high chromium cast iron， high manganese steel alloy.
Low carbon alloy steel ball has good toughness and low price， under same conditions， its service life than the low chromium cast lift ball 1 times above;
High manganese steel toughness is good， good in usability， low prices， its main characteristic is in larger shocks or under the action of contact stress， surface layer will quickly produce strain hardening， the strain hardening index is 5-7 times higher than the other materials， the wear resistance improved enhancement;
High chromium cast iron is a kind of excellent anti-wear performance of wear resistant material， but the toughness is low， prone to brittle and broken and expensive.
High carbon high manganese steel of main elements such as chromium， molybdenum alloy structural steel， high hardness， good toughness， the matrix organization are martensite， bainite or bainite ＋ martensite composite tissue. Ball hardness is about HRC60， the impact toughness of 15 or higher J/CM2， under the same working conditions， its service life， at least I times higher than that of high manganese steel ball.
Steel tempering heat treatment is the key， however， requires not only the overall resilience after tempering heat treatment 12 joule/CM2， and requires considerable plasticity and resistance to wear， but the general casting process can only achieve 3-5 joule， lead to broken rate is high， even high chrome casting balls， so the working strength is big， it is recommended to use forgings.
The manufacture technology of steel ball is to determine the key factors of its service life. If the steel ball surface or internal manufacturing flaws， such as shrinkage cavity and crack， transgranular， not only can reduce steel ball performance， even cause steel ball is broken. In the steel ball production， therefore， must formulate reasonable forging， casting and heat treatment process. Of high chromium cast iron ball， for example， vertical casting and the rational use of cold iron should be adopted， and strictly controlling the pouring temperature， which can make the steel ball in the casting has good solidification sequence and feeding conditions， the internal organization density is obtained， and weakened the phenomenon of coarse grains. Steel heat treatment process is decided to the implementation of its mechanical properties and the distribution of the carbide morphology. Due to contain a certain amount of chromium in steel components and other alloy elements， so how to make the alloy elements to form carbide hard spots role into full play， and make heat treatment process to consider a factor. In a word， make the reasonable production process and strict quality inspection methods， a prerequisite to ensure the using performance of steel ball.
To sum up， forging is better than that of castings， specific what steel ball is more appropriate to use according to their respective working characteristics and economic strength. As the saying goes， there is no best， only better， not to buy expensive， only buy right. Fareastball hope I can bring you a tangible economic and affordable.