Metalworking fluid is used to lubricate and cool workpieces, cutting tools or grinding tools during metal processing. In order to improve processing efficiency, workpiece precision and surface quality, and prolong the life of cutting tools and grinding tools, in addition to reasonably selecting cutting tools, Mold materials, geometric parameters, heat treatment specifications and processing volume depending on the processing conditions, metals also need to be selected correctly machining fluid.
1. What is metal cutting?
Cutting is a metal processing process. It uses cutting tools (tools or grinding wheels) with sharp edges to remove excess metal from the workpiece, so that the workpiece can obtain the specified shape, size and surface quality of the finished or semi-finished product . workpiece.
Metal cutting methods: sawing, turning, milling, planing, grinding, drilling, boring, reaming, tapping, drawing, etc.
Typical processing surfaces: inner circle, outer circle, void, plane.
Depending on surface quality: roughing, semi-finishing, finishing, superfinishing
Surface roughness: used to indicate the quality of the treated surface, the symbol is Ra, the unit is μm
According to the angle at which metal materials can be cut, they can be divided into
Turning materials: non-ferrous metals: aluminum, aluminum alloy, magnesium-zinc alloy, brass, lead bronze
Common materials: non-ferrous metals: copper, high-strength bronze,
Ferrous metals: cast iron, medium and low carbon steels
Difficult to cut materials:
Non-ferrous metals: titanium, nickel
High alloy steel: heat resistant steel, high speed steel, stainless steel,
High and low carbon alloy steel: manganese steel, nickel chrome steel, bearing steel, carbon steel, nickel chrome and copper alloy steel
Commonly used machining tools
Commonly used cutting tool materials include: high speed steel, tool steel, cobalt alloy, sintered carbide, cermet, cubic boron nitride, artificial diamond, etc. (general tool steel 200~300℃, high speed steel 600℃, cemented carbide 1000℃, cubic boron nitride 2000℃)
2. Classification of metal cutting fluids
Types of cutting fluids: oil-based (animal oil, vegetable oil, mineral oil), water-based (emulsion, microemulsion, synthetic fluid).
Ranking criteria
1. International classification standards
The international classification standard ISO 6743/7 —- 1986 includes a total of 17 categories, including 8 categories (MHA-MHH) of non-water-soluble metalworking fluids and 9 categories (MAA-MAI) of water-soluble metalworking fluids. The varieties are suitable for 44 different processing conditions such as cutting, grinding, EDM, thinning and rolling, extreme pressure, wire drawing, forging and rolling.
2. National standards
In my country, the equivalent of ISO 6743/7-1986 was adopted to formulate the national standard GB7631.5-89 “Classification of lubricant-related products (category L) Part 5: Group M (Metal processing) » Products focused on lubrication requirements This is a pure oil type, that is, MH type (also including MHG grease, wax, MHH soap powder, solid lubricant or its mixture). Mainly based on cooling requirements, it is an aqueous solution type, that is, MA type.
Category MH: oils
Pure L-MHA mineral oil is mainly used for heavy-duty cutting and sharpening (promoting the settling of iron powder).
L MHB fatty oil (or oil additive) + mineral oil is mainly used for fine turning of screws, gear cutting, shaving and pull pins.
L—MHC inactive extreme pressure cutting oil, mineral oil + inactive extreme pressure additives
Active extreme pressure cutting oil L—MHD, mineral oil + highly reactive sulfur series extreme pressure additives
Composite cutting oil L-MHE and L-MHF, mineral oil + oil additives and extreme pressure additives
Category MA: water-soluble cutting fluid
L-MAA anti-rust emulsion (50-80% oil)
L—MAB anti-rust lubricating emulsion, based on animal and vegetable fats or long-chain fatty acids
L-MAC extreme pressure emulsion contains an extreme pressure agent, suitable for intensive cutting such as threading and broaching.
L-MAD extreme pressure emulsion contains an extreme pressure agent, suitable for intensive cutting such as threading and broaching.
L-MAE microemulsion (oil content 10% to 30%), working fluid, emulsified particles less than 0.1 microns.
L-MAF extreme pressure emulsion, containing an extreme pressure agent, can be used for medium and heavy cutting treatments.
Chemically synthesized cutting fluid L-MAG
Extreme pressure chemical synthetic cutting fluid L-MAH
Mixture of L-MAI fat and paste and water
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