How much can the hardness of 40Cr quenching and tempering be achieved?

There should be no problem with the strength, I have also used 20CR to do the test before, using high-frequency local quenching, and the two ends can also be riveted (HRC41 at both ends, HRC45 in the middle) Because of the cost factor, I want to change to 40CR quenching and tempering, and the hardness is about HRC34. In this way, both ends can also be riveted, and there is a certain wear resistance. Will 40cr quenching and tempering become brittle to this hardness, or will there be a big change in strength?

For this quenching and tempering, we require 25-30HRC, and generally the quenching of this material can reach about 55HRC. The hardness adjusts the tempering temperature by itself.

In the past, I used to use 20cr middle and high frequency, but the cost was a bit high, so I wanted to use 40cr quenched and tempered. The hardness of HRC34 is because ETG100 does not need heat treatment, and the hardness is also about HRC35.

After 860 degree heat preservation and diathermy, the oil is hardened at about HRC52, and it can be tempered at 540 degrees for 100 minutes.

40cr belongs to low hardenability alloy quenched and tempered steel, steel grade: 40cr annealing hardness hbs: 207 end quenching test temperature |Normalize:

860 880 end quenching test temperature |End quenching: 850 5 Hardenability zone range: the upper limit is HRC| at the following distance (mm) from the quenching end:

59 hrc|at the following distance (mm) from the quenching end59 hrc|at the following distance (mm) from the quenching end: 58 hrc|at the following distance (mm) from the quenching end6:

57 HRC|at the following distance (mm) from the quenching end9:54 HRC| at the following distance (mm) from the quenching end12:48 HRC|at the following distance (mm) from the quenching end15:

43 HRC|at the following distance (mm) from the quenching end18:41 HRC|at the following distance (mm) from the quenching end21:39 HRC| at the following distance (mm) from the quenching end24:38

Dear, I am glad to answer for you: what is the hardness of 40cr after heat treatment; Hello 40cr quenching hardness is generally 830-860, the hardness after oil quenching is greater than that of the surface quenching hardness of 52-60hrc, and the flame quenching hardness can reach the highest hardness after quenching around hrc55. Because 40cr belongs to medium carbon steel, the hardness cannot be higher after quenching.

This steel has good hardenability, high strength and high fatigue strength, and also has good toughness. It is widely used to make gears, shafts, sleeves, etc. The tensile strength and yield strength of 40cr are about twenty percent higher than that of 40 steel.

The hardness of 40CR material after high frequency or medium frequency quenching can reach HRC48 53. 40Cr is the standard steel grade of GB in China, and 40Cr steel is one of the most widely used steels in the machinery manufacturing industry. After quenching and tempering treatment, it has good comprehensive mechanical properties, good low-temperature impact toughness and low notch sensitivity.

The hardenability of steel is good, it can be hardened up to 28 60mm when water quenched and 15 40mm when oil quenched. In addition to quenching and tempering, this steel is also suitable for cyanide and high-frequency quenching. The machinability is good, when the hardness is 174 229HB, the relative machinability is 60%.

The steel is suitable for medium-sized plastic molds.

The hardness of 38CrMoal after quenching and tempering is generally T235 and T265.

38crmoala is a special nitriding steel, generally used in the machine tool spindle and other places, before nitriding to quench and temper treatment, the hardness of the nitriding treatment is quite high, the hardness is above HV800, the hardening layer can be reached, the hardness, wear resistance is much better than 45 steel, but it is also higher than 45 steel.

38crmoal alloy structural steel

38Crmoal Features:

38CrMoal steel is an alloy structural steel of the CR-MO-AL series, which is a nitriding steel (nitriding steel), which is also an ultra-high strength steel. 38Crmoal steel is mainly used for gas nitriding, but also for ion nitriding and soft nitriding, the aluminum Al element in steel is the main alloying element to improve the hardness of the nitride layer, it forms highly diffuse aluminum nitride (ALN) with nitrogen, and its hardness is extremely high, up to 9 10 Mohs hardness. Due to the joint action of aluminum AL, molybdenum MO and chromium CR, the surface hardness of 38CrMoal steel after nitriding can reach 1100 1200HV, and the microstructure stability is good (can be used below 500);At the same time, they refine grains and improve the strength and hardenability of steel.

In addition, a small amount of molybdenum MO can also improve the thermal stability of the steel, eliminating the tempering brittleness of the steel during long-term heat retention at nitriding temperature and subsequent slow cooling.

Although 38crmoal steel has high fatigue strength and wear resistance, it is not very hardenable and can only be hardened to a size of 50mm thick. In addition, the cold deformation plasticity is low, and the welding performance is poor. After quenching and tempering 38Crmoal steel, the tempered sostenite structure can be obtained, and when the surface is nitrided, the ferrite structure is easy to dissolve a large amount of nitrogen to form iron nitride with extremely high hardness and aluminum nitride, which enhances the fatigue strength, surface hardness, wear resistance, corrosion resistance, heat resistance and seizure resistance of steel surface.

After nitriding, there is generally no quenching treatment, so there is no quenching deformation problem.

38Crmoal Chemical Composition:

Carbon C:; Silicon SI:;

Manganese mn:; Sulfur S: permissible residual content

Phosphorus p: permissible residual content

Chromium cr:; Nickel Ni: permissible residual content

Copper Cu: permissible residual content

Molybdenum mo:; Al-al:.

38CrMoal Implementation Standards:

gb /t 3077-2015

38 Crmoal Heat Treatment Specification:

Quenching 940, water-cooled, oil-cooled; Tempered 640, water-cooled, oil-cooled.

38Crmoal Mechanical Properties:

Tensile strength b (mpa): 980

Yield strength s (mpa): 835

Elongation δ5 (%14

Section shrinkage 50;

Impact power AKV (J): 71;

38CrMoal Applications:

It is mainly used for nitrided parts with accurate dimensions after heat treatment, or various nitriding parts with low impact load and high wear resistance, such as boring bars, grinding machine spindles, automatic lathe spindles, worms, precision screw rods, precision gears, high-pressure valves, valve stems, gauges, models, rollers, imitation molds, cylinder blocks, compressor piston rods, governors, rotating sleeves, fixed sleeves on steam turbines, various wear-resistant parts on rubber and plastic extruders, etc.

38Crmoal Main Specifications:

38Crmoal Round Bar, 38CrMoal Rolled Bar, 38CrMoal Forging Bar, 38CrMoal Forging, 38CrMoal Plate, 38CrMoal Forging Ring.

Hello, 35CRMO is a commonly used alloy structural steel with high strength and toughness, which is suitable for manufacturing high-strength and high-toughness mechanical parts. For the quenched and tempered hardness of 35CrMo steel, it needs to be determined according to the specific heat treatment process. Generally speaking, the quenched and tempered hardness of 35CRMO steel can reach about 40 45hrc, and if a more stringent heat treatment process is adopted, the quenched and tempered hardness can reach 50 55hrc.