General machinery parts production
- Commodity name： General machinery parts production
- Commodity ID： 1191888388001255424
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Keywords:
Quenched-and-tempered components in general machinery—such as bolts, crankshafts, and intake valves—are typically made from medium-carbon steel or medium-carbon alloy steel. These parts undergo quenching followed by high-temperature tempering to produce a microstructure—tempered sorbite—that exhibits excellent overall mechanical properties. For such quenched-and-tempered components, especially those that are not subjected to further machining after tempering—for example, bolts and intake valves—it is essential to control the carbon potential during the heat treatment process to prevent decarburization of the surface, which could reduce the part’s strength.
Product Details
Quenched-and-tempered components in general machinery—such as bolts, crankshafts, and intake valves—are typically made from medium-carbon steel or medium-carbon alloy steel. These parts undergo quenching followed by high-temperature tempering to produce a microstructure—tempered sorbite—that exhibits excellent overall mechanical properties. For such quenched-and-tempered components, particularly those that are not subjected to further machining after tempering—for example, bolts and intake valves—it is essential to control the carbon potential during the heat treatment process to prevent decarburization of the surface, which could reduce the part’s strength.
Many components of general-purpose machinery feature carburized parts, particularly stamped parts, because their surfaces must possess sufficient hardness when in contact with other metal components. Examples include the speed-control flyweights on speed-control gears, the pressure plates and pawls on the start-up pull plate, the rocker arms, and the speed-control cap, among others.
Metallographic structure of the speed-regulating flyweight after carburizing: the surface consists of acicular martensite with high hardness, while the core remains ferrite with a small amount of pearlite.
Nitriding: Nitrocarburizing involves the simultaneous diffusion of nitrogen and carbon atoms into the surface of a component. When nitrogen diffusion predominates, the process is referred to as nitriding; when carbon diffusion is dominant, it is called cyaniding. In general machinery, nitrided components primarily include intake and exhaust valves, valve spring seats, tappet limit plates, and camshafts, all aimed at enhancing surface hardness and improving wear resistance.
The principle of induction heating heat treatment is to utilize the heat generated by eddy currents induced in the workpiece to heat its surface, a localized area, or the entire workpiece, followed by rapid cooling. This process is classified into high-frequency, medium-frequency, power-frequency, and ultra-audio categories.
Induction hardening can enhance the local hardness and strength of parts, features short heating times, minimal workpiece distortion, energy savings, and low environmental pollution, making it widely used. It is suitable for medium-carbon steels and medium-carbon alloy steels, such as crankshafts, small-end caps of intake valves, adjusting nuts, and valve tappets in general machinery products.
Crankshaft:
It is subjected to cyclic gas pressure, inertial forces of the crankshaft–connecting rod mechanism, torsional and bending stresses, and impact loads. Moreover, in high-speed internal combustion engines, torsional vibrations also occur, which can induce substantial stresses.
It is required to have high strength, as well as adequate impact toughness, bending strength, torsional strength, and fatigue strength, along with high wear resistance at the journal.
Medium-speed internal combustion engines utilize quenched-and-tempered carbon steel or alloy steel, such as 45, 40Cr, 45Mn2, and 50Mn2, as well as ductile cast iron.
Business Hotline
Address: No. 7, Meijia Road, Nan’an District, Chongqing
Email: fenghai@cqfenghai.com
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Company Phone：023-61966749
Company email：fenghai@cqfenghai.com
Recruitment Hotline：023-61966751
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