ASTM 5140

Alloy steels: 5140 standards: ASTM A29 / A29M-04 \"characteristics and application: ASTM5140 is the most commonly used alloy steels, tensile strength, yield strength and its quench-hardening ability are better than no. 40 steel is high, but the weldability Co., LTD, have formed the tendency of crack. ASTM5140 used for more important conditioning parts, such as alternating load of parts, medium speed work and medium load parts. ASTM5140 hardening to load and high wear resistance and very big impact, and no parts, such as gear, sleeve, shaft, crankshaft, pins.

"Mechanical properties: tensile strength σ b (MPa) : frequency 980 (100) the yield strength σ s (MPa) : 785 (80) at the frequency δ 5 (%) : quartile 9 area reduction ψ (%) : quartile 45 impact energy Akv (J) : 47 quartile impact toughness values α kv (J/cm2) : 59 quartile (6) hardness: more than 207 HB sample size: sample blank dimensions for 25 mm standard and metallographic organization" heat treatment, heat treatment specification: quenching 850 ℃, the oil cold; Tempering 520 ℃, water, oil, and cold. "Delivery status: to heat treatment (is fire, annealed or high temperature tempering) or not heat treatment state delivery, delivery status should be indicated in the contract.

Editor this period of characteristics

5140 in carbon steel is a steel, cold heading steel mold. The steel prices moderate, easy processing, the proper heat treatment later can gain some toughness, plastic and wear resistance. Is the fire can promote organization nodularity, improve hardness of less than 160 HBS blank the cutting performance. In 550 ~ 570 ℃ temperature follows, this steel has the best comprehensive mechanical properties. The steel its quench-hardening ability is high, suitable for high frequency quenching, surface hardening process such as flame hardening, etc.

Editor this period of application

After the conditioning is used in the manufacturing of the medium under load and medium speed work mechanical parts, such as car's steering knuckle and after half shaft and machine gear wheel, shaft, worm, spline shaft, top set, etc.; The quenching and tempering used in the manufacture of temperature after under high load, impact and medium speed work parts, such as gear, spindle, oil pump rotor, slider, set of ring, etc.; The low temperature quenching and tempering after under heavy load, used in the manufacture of low impact and abrasion resistance, and section with the entity in 25 mm thickness of the following parts, such as the worm, spindle, axle, set of ring, etc.; After the tempering and high frequency surface hardening used in the manufacture of high surface hardness and wear resistance and no impact parts, such as gear, sleeve, axle, spindle, crankshaft, mandrels, pins, connecting rod, screw, nut, intake valve, etc. In addition, the steel and is suitable for the manufacture of seepage of carbon and nitrogen treatment of transmission parts, such as larger diameter and low temperature toughness good gear and axis. Elastic modulus elastic modulus E (20 ℃) / MPa 200000 ~ 211700, shear modulus G (20 ℃) 80800 850 ℃ quenching heat treatment, oil cold; Tempering 520 ℃, water, oil, and cold. 40 Cr hardening hardness of HRC52-60, flame hardening can achieve HRC48-55. Nitriding process 5140 steel are nitriding steel that contains the elements to nitration. 5140 after nitriding process can obtain higher surface hardness. 5140 after the tempering nitriding process can reach the highest hardness HRA72 ~ 78, namely HRC43 ~ 55. Nitrogen chemical a process route: forging-annealing-rough machining-conditioning-precision machined-except stress-coarse grinding-nitriding-fine grinding or grind. Because nitriding thin and brittle, so to a higher intensity heart department organization, so want to go to the conditioning heat treatment, get the tempering saxhlet body, improve mechanical properties of heart and nitriding quality. Tufftriding is active nitriding, now more commonly used is gas nitriding. Welding 5140, in order to prevent the matrix for heat, causing seam internal quench quenching crack. After soldering conditioning before had better add again is fire. Crystallization in easy segregation, the perspective of crack (a kind of hot crack) is more sensitive, easy arc welding in pit and in welding seams of concave cracking. Carbon content is higher, the fast cooling to easily get cold crack sensitive hardened organization (martensite organization). Content in the cold speed is bigger, very easy to form hard brittle high carbon martensite and make embrittlement of content.

Editor this period of welding process

1, general in annealing (is fire) state welding. 2, welding method is not restricted 3, with larger line energy, an appropriate increase in temperature, general temperature and temperature between layers can be controlled in 250 ~ 300 ℃ between. 4, welding materials should guarantee the deposited metal melting the composition and mother material basic same, such as J107-Cr 5, welding shall be promptly after conditioning heat treatment. If the quenching and tempering treatment in time have difficulty, can be in the middle of annealed or in the preheated temperature higher than the heat preservation period of time, to rule out diffusion hydrogen and soften the organization. To structure is complex, weld more products, can be in after a certain number of welding seam, a middle annealing.