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 Posted: Fri 10:57, 07 Jan 2011 Post subject: stivali ugg Two kinds of quenching oil to the spri |
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Heat the oil on the spring two quenching effect of the quality of
5O8510j5O4552251046352O5O512mm thick 60Si2Mn spring of quenching hardness up to 485HB, the lowest 321HB, hardness and uneven. Only a few values to meet the requirements. Shows that the effective thickness of oil on the 60Si2Mn spring 12mn1 cooling rate and maximum high temperature cooling rates are not enough. Yu-Y15 in a n this fast quenching oil, 14mm thick, spring 60Si2Mn quenching hardness up to 550HB, the lowest 463HB, average 505HB, the hardness is more uniform, the cooling performance can meet the 14mm thick, spring quenching 60Si2Mn requirements. After a year of use and exploration of this Yu Y15II fast quenching oil to meet the following thickness of 14mm hardened 60Si2Mn spring, and a thickness of about 20mm hardened 5OCrVA spring, in the hardenability of the entire cross section can be obtained good mechanical properties, and kept the piece has a good brightness. A, £. , 3_J1 purpose is to spring hardening of the austenitic steel, hardened to form a reasonable cooling martensite and then tempered to achieve the required organization and performance. The key is to ensure the quenching medium hardened spring steel C curve in the tip of the nose at the cooling rate should be sufficiently large to avoid the formation of the supercooled austenite pearlite or bainite. 5OCrVA by the steel and steel 60Si2Mn undercooled austenite transformation curve and end quenching curve indicated that the martensite formation temperature of about 300C, so the appropriate cooling medium reaches the tip of the nose should be the maximum cooling rate in the 300C the following appropriate cooling rate, in order to achieve not only can but also to reduce the deformation of hardened quenching purposes. Observed data in table 1 shows, N32 oil (both old and new), t is ≥ 4.8S, and 60Si2Mn steel \undue changes in temperature bainite, Figure 1 (c). The hardness of the production site (Table 5) shows that the uneven use of N32 oil quenching and low hardness, which is due to 71r1 ... less than 60Si2Mn steel \sake, which is greater than the effective thickness 12II11 \N32 oil hardening steel of 50CrVA is appropriate, but the effect is worse than with the Y15-lI fast quenching oil quenching, see Figure 1 (d). Table 2 data show that: Y15-II fast quenching oil vapor film stage is shorter, and maximum cooling rate occurs at higher temperatures. This avoids the first precipitation of supercooled austenite eutectoid ferrite and bainite,[link widoczny dla zalogowanych], while the low temperature high enough cooling rate (cooling rate of 300C is usually representative of the low-temperature quenching medium cooling rate), are the ideal organization. Distinguished by metallographic test, 60Si2Mn quenched steel specimens with Y15-II is higher than the organizational level with N32 oil quenching; 50CrVA spring steel heat treated by two kinds of quenching medium, from the organizational form of the Y15-II fast quenching oil smaller than the N32 has a more uniform temper oil troostite organization,[link widoczny dla zalogowanych], shown in Figure 1 (e),[link widoczny dla zalogowanych], (f). Although the fracture surface from Figure 2, not much different picture point of view, but the contrast Lashen data showed that, Y15-II oil heat, the material strength slightly higher than the N32 engine oil, plastic index higher than the N32 oil quenching, mainly Y15-II is due to characteristics of the oil temperature and cooling rate are better than the N32's largest oil's sake. Thus, Y15-II the use of fast quenching oil, on the one hand to ensure that the 14 × 1O0 of 60Si2Mn (18 × 1O0 of 50CrVA) spring quenching cross section in all: it also ensures the mechanical properties after heat treatment. 4 Conclusion (1) in the original oil in the old N32 can not add new oil cooling characteristics have a greater improvement,[link widoczny dla zalogowanych], N32 effective thickness of the oil is not suitable for mass production of more than 12mm spring. (2) Y15-II fast quenching oil has better cooling properties of materials used Y15-11 60Si2Mn fast quenching oil for heat treatment. Level of the material microstructure and tensile ductility after quenching oil is better than N32. (3) for large cross-section (12,111,111 or so thick) 60S2Mn spring Y15-II by fast quenching oil treatment, can improve the mechanical properties of materials. Better meet product performance requirements. Tin
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