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hunan neptune pump

What is the best material for the multi-stage pump long shaf

Source:未知|Popularity:0|release date:2020-04-02 14:16:18
Blanks and materials
(I) Roughness of shaft parts
Shaft parts can be selected as blanks such as bar stocks and forgings according to the requirements of use, production type, equipment conditions and structure. For shafts with relatively small outer diameters, bar materials are generally used; for stepped shafts or important shafts with widely different outer diameters, forgings are often used. This saves material and reduces the workload of mechanical processing. Improve mechanical properties.

According to the different production scales, there are two methods of forging blanks: free forging and die forging. Small and medium batch production mostly adopts free forging, and large batch production uses die forging.

(II) Material of shaft parts
Shaft parts should choose different materials and adopt different heat treatment specifications (such as quenched and tempered, normalized, quenched, etc.) according to different working conditions and use requirements to obtain certain strength, toughness and wear resistance.

40Cr is a common material for shaft parts. It is cheap and can be obtained after quenching and tempering (or normalizing). It can also obtain comprehensive mechanical properties such as higher strength and toughness. The surface hardness after quenching can reach 45 ~ 52HRC.

40Cr and other alloy structural steels are suitable for medium-precision and high-speed shaft parts. After quenching and tempering, this type of steel has good comprehensive mechanical properties.

Bearing steel GCr15 and spring steel 65Mn, after quenching and tempering and high-frequency surface hardening, the surface hardness can reach 50-58HRC, and it has higher fatigue resistance and better wear resistance, and can manufacture shafts with higher accuracy.

40Cr is widely used in mechanical manufacturing, and this steel has good mechanical properties. This is a medium carbon alloy steel with good hardening performance. 40Cr can be hardened to HRC45 ~ 52. So if you need to improve the surface hardness, but also want to take advantage of the superior mechanical properties of 40Cr, the surface is often quenched and tempered, and the hardness can reach 55-58HRC, so that you can get the required high surface hardness and maintain your heart. Good toughness.

Quenching process
40Cr quenched at 850 ℃, oil-cooled; tempered at 220 ℃, water-cooled, oil-cooled, and air-cooled. 40Cr surface quenching hardness is 52-60HRC, flame quenching can reach 48-55HRC.

40Cr is a nitrided steel, and its elements are conducive to nitriding. 40Cr after nitriding can obtain a higher surface hardness, after quenching and tempering 40Cr, the highest hardness can reach 72 ~ 78HRA, and the core hardness can reach 43 ~ 55HRC.

Nitriding workpiece process route: forging-annealing-rough machining-quenching and tempering-finishing-stress relief-rough grinding-nitriding-finishing grinding or grinding. Because the nitrided layer is thin and brittle, it requires a high-strength core structure. Therefore, it is necessary to perform a quenching and tempering heat treatment to obtain tempered sorbite to improve the mechanical properties of the core and the quality of the nitrided layer.

42CrMo steel belongs to the plastic mold steel among the mold steels in terms of material classification. It has good mechanical properties and processability and is widely used. There are mainly two types of materials, plate and round rod, of which plate is used for mold processing For production, round rods are used in mechanical direct machining parts or shaft parts, which have been recognized by the industry.

42CrMo steel belongs to ultra-high strength steel, with high strength and toughness, good hardenability, no obvious tempering brittleness, after quenching and tempering, it has higher fatigue limit and resistance to multiple impacts, and good low temperature impact toughness. 42CrMo steel is suitable for manufacturing large and medium-sized plastic molds that require certain strength and toughness.

Mechanical properties
Hardness: Annealing, 255 ~ 207HB, indentation diameter 3.8 ~ 4.2mm; quenching ≥60HRC, Cr12MoV sheet hardenability, hardness, strength and toughness after quenching and tempering are higher than Cr12, the work under 300 ~ 400mm diameter can be completely Hardened, hardened deformation is small, but poor plasticity at high temperature. Cr12MoV sheet is mostly used to make compound molds and tools with large cross sections, complex shapes and heavy workloads.

Difference between 45 Baidu Steel and 40Cr, 42CrMo
45 is a high-quality carbon structural steel with a carbon content of 0.42--0.50%, a tensile strength of 610 MPa, and a yield point of 360 MPa; it is used for general shaft parts.

40Cr is an alloy structural steel with a carbon content of 0.37--0.45%, a chromium content of 0.8--1.1%, a tensile strength of 1000 MPa, and a yield point of 800 MPa; it is used for the shafts of large load parts.

42CrMo is an alloy structural steel with a carbon content of 0.38--0.45%, a chromium content of 0.9--1.2%, a molybdenum content of 0.15--0.25%, a tensile strength of 1100MPa, and a yield point of 950MPa. The load is large and parts with high reliability are required.

You can choose 2Cr13 if it is corrosive. The material characteristics are as follows:
2Cr13 is a martensitic stainless steel, which is magnetic and has good hardness. It needs to be preheated for welding. Austenitic stainless steel electrodes for Q235 welding do not need to be preheated, such as A302 and A307.
Controls the dilution rate of the weld during welding, does not swing the welding, and uses a smaller current

Scope of application
2Cr13 stainless steel has high hardness and good corrosion resistance in the quenched state. Many of them are used for cutting tools. They are "blade grade" martensitic steel and also used for surgical tools. They are similar to the earliest stainless steels such as Brinell high chromium steel.

Mechanical properties
Tensile strength σb (MPa): quenching and tempering, ≥635
Conditional yield strength σ0.2 (MPa): quenching and tempering, ≥440
Elongation δ5 (%): quenching and tempering, ≥20
Section shrinkage ψ (%): quenching and tempering, ≥50
Impact work Aku2 (J): quenching and tempering, ≥63
Hardness: annealing, ≤223HB; quenching and tempering,> 192HB
Heat treatment specifications and metallographic structure:
Heat treatment specifications: 1) annealing, slow cooling at 800 ~ 900 ℃ or rapid cooling at about 750 ℃;
2) Quenching, oil cooling at 920 ~ 980 ℃;
3) Tempering, rapid cooling at 600 ~ 750 ℃.
Metallographic structure: the organization is characterized by martensite type.
In summary of the above, etc., the shaft material is not the best, only the most suitable material is selected according to the working conditions.