Use metallographic microscope to observe the characteristics and types of ferrous metals
Ferrous metal materials are usually formed by smelting iron and steel. Iron commonly used in industry can be divided into
Pure iron, steel and cast iron are briefly described as follows:
1. Pure iron for industrial use: iron-carbon alloy with a carbon content of less than 0.02%. It is soft and ductile, but is not suitable for use.
On the construction materials. Mainly used as electromagnetic material, tinplate material, and alloy steel raw material.
2. Carbon steel: Iron-carbon alloy with a carbon content of 0.02 to 2.0%. Properties depend on chemical composition, processing and heat treatment
It is different. When normalizing the tissue, the carbon content is determined according to the nature.
According to carbon content:
a Low carbon steel: carbon content 0.02~0.3%.
b Medium carbon steel: carbon content 0.3~0.6%.
c High carbon steel: carbon content 0.6~2.0%.
"Ordinary carbon steel" refers to a steel with a carbon content of 0.1 to 0.2%, good ductility, machinability, and weldability.
The surface is smooth after processing and is often used as a general structural material. "Carbon steel for machinery" refers to steel with a carbon content between low and medium carbon.
Content range, properties are better than general structural carbon steel, good processing properties, uniform texture, often used as machine parts materials.
If other special alloy elements are added to the iron-carbon alloy, a special iron metal will be produced, which is an alloy.
steel. The representative alloy steel is "stainless steel", whose main alloying element is added with more than 2% "chromium".
It can improve corrosion resistance and rust resistance in different environments.
3. Cast iron: An iron-carbon alloy usually containing 2.0 to 6.67% carbon. Cast iron has a lower melting temperature, has good fluidity when melted, and is relatively cheap.
In the past, the strength of castings was not good, but in recent years many cast irons with good mechanical properties have been developed.
