Metallic material processability
DATE：2019/11/19 8:58:49 / READ： / SOURCE：This station
Metallic material processability
Metal materials can have different processing routes according to the shape and performance requirements of the parts, and some of the process routes are complicated, so the process performance requirements of the materials are high.
(1) Processing route of metal materials
There are roughly three types of processing routes for metal materials:
1) General parts with low performance requirements
Mainly used carbon steel, cast iron and other common materials, the process route is:
Hair ring (obtained by casting or press working) a heat treatment (normalizing or annealing) → machining → parts
2) General parts with higher performance requirements
For example, various alloy steels, shafts made of high-strength aluminum alloys, gears, and the like. Its route is:
Blank (obtained by casting or press working) - heat treatment (normalizing or annealing)
Rational (quenching + tempering or solid solution + aging treatment or surface heat treatment) a finishing → parts
3) Precision parts with high dimensional accuracy requirements
For example, precision screw rods, masts, and oil pump precision parts made of alloy steel. Its route is:
Blank (obtained by casting or press working) → heat treatment (normalizing or annealing) → roughing → heat treatment (quenching + tempering or solid solution + aging treatment or surface heat treatment) → finishing → stabilization treatment (stress relief annealing or seepage) Nitrogen)→grinding and twisting→stabilization treatment (stress relief annealing)→parts
(2) Processability of metal materials
Casting performance
Casting performance is characterized by fluidity, shrinkage, hot cracking tendency, segregation and gettering. Materials for casting and forming should have good castability.
In general, alloys with near eutectic compositions have the best casting properties, such as gray cast iron, silicon aluminum alloy (aluminum silicon cast alloy) and the like. Compared with other cast irons, gray cast iron has good castability. Due to the slightly poor fluidity and slightly shrinkage of ductile iron, it is easy to form shrinkage, shrinkage and white mouth, so its castability is slightly lower than that of gray cast iron. Cast steel has poor fluidity, large shrinkage, large segregation tendency, high melting point, and poor casting properties, and is also prone to cold cracking. In cast copper alloy, brass casting performance is good, easy to form concentrated shrinkage holes; while tin bronze is not as good as brass, easy to form shrinkage; special bronze such as aluminum bronze, easy to inhale and oxidize and form concentrated shrinkage holes, so easy to obtain Dense castings. Cast aluminum alloys are easily inhaled and oxidized, and the strength of the casting decreases significantly with increasing wall thickness.
Metal materials can have different processing routes according to the shape and performance requirements of the parts, and some of the process routes are complicated, so the process performance requirements of the materials are high.
(1) Processing route of metal materials
There are roughly three types of processing routes for metal materials:
1) General parts with low performance requirements
Mainly used carbon steel, cast iron and other common materials, the process route is:
Hair ring (obtained by casting or press working) a heat treatment (normalizing or annealing) → machining → parts
2) General parts with higher performance requirements
For example, various alloy steels, shafts made of high-strength aluminum alloys, gears, and the like. Its route is:
Blank (obtained by casting or press working) - heat treatment (normalizing or annealing)
Rational (quenching + tempering or solid solution + aging treatment or surface heat treatment) a finishing → parts
3) Precision parts with high dimensional accuracy requirements
For example, precision screw rods, masts, and oil pump precision parts made of alloy steel. Its route is:
Blank (obtained by casting or press working) → heat treatment (normalizing or annealing) → roughing → heat treatment (quenching + tempering or solid solution + aging treatment or surface heat treatment) → finishing → stabilization treatment (stress relief annealing or seepage) Nitrogen)→grinding and twisting→stabilization treatment (stress relief annealing)→parts
(2) Processability of metal materials
Casting performance
Casting performance is characterized by fluidity, shrinkage, hot cracking tendency, segregation and gettering. Materials for casting and forming should have good castability.
In general, alloys with near eutectic compositions have the best casting properties, such as gray cast iron, silicon aluminum alloy (aluminum silicon cast alloy) and the like. Compared with other cast irons, gray cast iron has good castability. Due to the slightly poor fluidity and slightly shrinkage of ductile iron, it is easy to form shrinkage, shrinkage and white mouth, so its castability is slightly lower than that of gray cast iron. Cast steel has poor fluidity, large shrinkage, large segregation tendency, high melting point, and poor casting properties, and is also prone to cold cracking. In cast copper alloy, brass casting performance is good, easy to form concentrated shrinkage holes; while tin bronze is not as good as brass, easy to form shrinkage; special bronze such as aluminum bronze, easy to inhale and oxidize and form concentrated shrinkage holes, so easy to obtain Dense castings. Cast aluminum alloys are easily inhaled and oxidized, and the strength of the casting decreases significantly with increasing wall thickness.
Author：admin