Abrasive features and application
Browm fused alumina
High hardness and toughness
It is suitable for grinding medium and high tensile strength
Metal such as ordinary carbon steel,alloy steels,malleableCast iron, hard bronze,etc.
white fused alumina
Its hardness is hight than that of A.its grains are easily broken.the edges of the grains are sharp and of excellent cutting performance.only small quantity of heat is created use.
It ls used for grinding harder material and metals sensitive to heat such as chilled steel.high carbon steel,ordinary high speed steel,alloy steel.it is mainly suitable for the grinding and forming grinding of instruments,cutting tools,mouldings,gears,thresds,thin-wall parts,etc.
Pink fused alumina
Its hardness is close to,but touguness higher than thatof WA.the edges of its grains are sharp andcan be kept well.it is also excellent durability.
It is suitable for the grinding of chilled steel,cutting tools and workpieces of alloy steel as well as the precision grinding of messuring tolls and parts of instruments and appratus,etc.
Monocystalline fused alumina
Its hardness is higher than of A and WA.It grains and ball-shaped single crystals with outstanding multi-corner edges and strong impact strength,etc
It is suitable for the grinding of stainless steel,high canadium-high speed teel and the workpieces in high toughness ans being easily-deformed and burnt.
Microcrystalline fused alumina
Its grains are composed of small crystals in high toughness and strong strength ans of excellent self-sharpening performance.
It is suitable for the grinding of ball-bearings,stainless steel and special nodular cast iron as well as forming grinding,infeeding grinding and other precision grinding,etc.
Mixture of WA and A
It posseses the advantages of both A and WA
It is suitablefor the grinding of nodular cast iron crankshaft and other workpieces.
Green silicon carbide
It is in high hardness and brittle.its grain edges are sharp and it is if excellent capacity of heat-transmission.
It is suitable for the grinding of cutting tools and workpieces of hard alloy,and non-ferrous metal and non-metal materials,etc
Black silicon carbide
It is high hardness and brittle. Its grain edges are sharp and it is of a certain capacity of heat-transmission.
It is suitable for the grinding of non-ferrous and non-metal materials.
The crystal size is very small,only about 0.3m.it has good self-sharpening and cut efficiency.and it isn t apt to burn the working piece.the durability and serving life of the grinding wheels are 2-5 times that of common.
It is suitable for alloy tool steel,high speed tool steel,heat-resisiting steel,bearing steel,stainless steel,etc,wtich are difficult processed by common abrasive materials.
For rough grinding and cutling
For common semi-precision grinding
For common fine grinding
For polishing and threading
For mirror-surface grinding and finer polishing
Recommended applications of wheels in the aspect of grain size
Snagging,Deburring and Cutting –off,etc
Surface,Cylindrial and Cenntreless gring
Precision Grinding and Cutter Sharpening
Precision Grinding，Honing and Thread Grinding
W20 and more
Lapping and Mirror Finish Grinding
600# 30 ~31
800# 22 ~18
The selection of abrasive material
High rigidity, strong flexibility,low price,can be used widely
Suitable for normal steel grinding,rough grinding, higher anti-pulls intensity metal as well,carbon steel, alloy steel,malleable cast iron hard bronze normal grinding,cut-off, free grinding
White aluminum oxide
Higher rigidity and weaker flexibility than A. good grinding function,low grinding heat
Suitable for the work pieces made of materials: Chilled steel,high-speed steel,highcarbon steel,which of strong intensity,high hardness grinding,also used to process thread,gear,components
Sharp cutting, good edges holdout,durable,stronger flexibility than WA
Suitable for form grinding,knives,measuring instrument,measuring appliance components,thread work piece components,micro finishing and other high smooth finish surface processing
Only no harder than boron carbide and diamond,friable, its girt is sharp,and thermal conductivity
Suitable for grinding hard alloy,optical glass, vitrify gem, agate,honing cylinder sleeve and other hard friable materials
Harder than corundum, crisper,less flexibility
Suitable for process weak tensile strength metallic and nonmetallic material,i.e.cast iron, brass,aluminum, stone material, wood material,glass,vitrify,fireproof material,rubber,leather,plastic and so on
Harder, more flexible than A,WA,single pellet spherical crystal(type),and anti-crumbliness
Suitable for grinding stainless steel, highvanadium highspeed steeland high toughness hard materials and distorting and burning work
The selection of hardness of grinding wheel
When grinding hard materials,choose soft abrasive tools,otherwise,choose hard abrasive tools.
Hard material is difficult to grind,and grit can be easily rubbed obtusely,so choose softer tool. Soft material is good at grinding, and grit may not rub obtusely easily, so choose harder tools.
Cut-in grinding external outer circle should be chosen softer abrasive tools then longitudinal feed grinding outer circle.
Avoid burning work pieces.
When forming grinding and grinding discontinuous surface, choose hard tool.
Guarantee right geometrical shape.
Plane grinding into the abrasive hardness should be soft,end face grinding should be softer than circular grinding. When grinding the work piece and abrasive, large contact surface or large amount of feed, grinding wheel should be soft.
Lapping tool and work piece contact is large, abrasive easily wear, grinding heat increase, easy to burn the work piece.
Internal grinding should choose harder tools than the outer circle and plane grinding.
In grinding, grinding tool linear velocity is low, so should choose higer hardness.
Sharpening knives should choose softer grinding wheel.
When used for sharpening knives,the work piece radiation condition is not good, may easily burn out or crack,so choose H-L hardness.
The hardness of high-speed grinding wheel should be 1-2 grade lower than normal grinding wheel.
The grinding wheel rotating at high speed under high dynamic hardness,so the hardness should be lower.
Grinding with coolant is higher than dry grinding.
Dry grinding work piece easy fever, choose 1-2 level softer grinding wheel than the coolant.
How to choose grinding wheel grain
The grain of the grinding wheel is the measurement of grit size. The choice of it has a direct influence on surface roughness and grinding efficiency of work piece. In general, high grinding efficiency use coarse-grained grinding, but the surface roughness of the work piece is poor. With a fine-grained grinding wheel, the surface roughness of work piece is better, but the grinding efficiency is low. In short, on the premise of meet the requirement of the work piece surface roughness, in order to ensure higher grinding efficiency, granularity coarser grinding tool should be chosen.
malleable cast pieces,
For the inner circle,cylindrical,planar,centerless,tool grinder and various special grinding machine,semi-finish grinding
For ultra fine
General fine grinding
Super fine grinding
Grit size of abrasive tools indicates the geometric dimensions of abrasive grains.abrasive grains can be divided into 41 grit No.in accordance with the dimensions of abrasive grains stipulated in china national standard.
The selection of grit sizes has direct influences on the surface roughness and cutting efficiency of workpieces.Generally,the wheels in big sizes possesses high cutting efficiency,but the surface roughness of the workpiece is worse.whereas the wheels in finer sizes possesses low cutting efficieny, but the surface roughness is better.in short,with the prerequisite of meeting requirements on the roughness,it is betterto select the abrasive tools of coarse grains to guarantee high cutting efficiency.
The hardness of abrasive tools indicates the difficulty of abrasive grains falling off the surface of the abrasive tools in cutting.
1.Generally,the grinding wheels in soft hardness are used for cutting harder workpieces,whereas the wheels in a bit higher hardness are used for cutting soft workpieces.
2.In the process of cutting,if the workpieces is touched greatly or the feeding is large,it is available to select soft hardness.for forming-grinding,it is better to select the wheels in higher hardness to guarantee precision of the workpieces.
3.When grinding the workpieces with weak capcacity of heat-transmission and cutting tools,it is better to select softer hardness to avoid burning and annealing.
4.When grinding at high speed,it is better to select softer hardness;the hardness in dry grinding should be softer than that in wet grinding.