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 Posted: Sat 19:03, 18 Dec 2010 Post subject: ugg prezzo 1Cr5Mo pipe weld heat treatment quality |
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1Cr5Mo pipe weld heat treatment quality assessment index of
∞ Ⅲ one hundred and eleven Emirates 1 ton ∞ ∞} f Lu Kang Jidong, etc.: 1Cr5Mo pipe weld heat treatment quality assessment index of affected zone and base metal hardness was determined to do was weld, heat affected zone, the base metal at least in each region Measure 5 points, taking the average test results are presented in Table 3 Table 3 Lan hardness test results for construction of 3 to discuss the different heat treatment after welding temperature, consistent with the provisions of the holding time. The principle is to ensure the greatest possible relaxation of residual stress without causing adverse effects on the joint properties. But for the post weld heat treatment quality assessment indicators have different requirements. For example, some specifications only require that the inspection record heat curve, and its heat treatment qualified as acceptable quality standards. Others are required to check the records of heat treatment temperature curve after passing the joint assessment of the hardness value as indicators but the specific provisions for the hardness values, the norms have different approaches. For example, GBJ236 - 82 ~ (on-site equipment, industrial pipe welding engineering construction and acceptance,[link widoczny dla zalogowanych], \: carbon steel base material should not exceed 120; steel should not exceed 125 base metal, such as the hardness exceeds the set, should be re-heat treatment, heat treatment methods still need to check the required hardness. SDJ51 - 82 ~ Power Construction construction and acceptance of technical specifications - power plant welding section, \, HB ≤ 250, ≥ 2 chromium steel, biB ≤ 300. The latest version of the AEB31.3-1996 in the different materials, for maximum hardness value of joint requirements. For the chromium content of 0.5 ~ 2 alloy steel to provide maximum hardness 225HB joints studied in this paper 1Cro with steel connectors for discussion the following points: (1) joint maximum hardness of heat treatment quality assessment index as a more scientific. As the base metal heat treatment may result in decreased hardness , only the general provisions of the weld and heat affected base metal hardness Medical hardness HB value is 100 or 120 plus 125, is too broad and difficult to master. If the present study, 4 for the welded specimens. Despite its hardness to meet the mother of material requirements of HB +100, but obviously does not meet the requirements of the residual stress level. And SDJ51 \indicators, both for operation and easy to compare inspection. to ensure that the true test results, stable and reliable. For 1Cr5Mo steel, consider the construction site conditions, proposed to HB 225 as the maximum acceptable quality evaluation index treatment (2) the quality of welding and heat treatment system qualified, the qualified joint stiffness, residual stress effects are obvious. residual stress from the test results of this paper can be seen that residual stress reduces the peak 20 - 50 ~ 4. It should be noted that, when Yan length of the residual thermal stress little effect on peak reduction. In fact, only an appropriate increase in the peak heating temperature, the peak residual stress may be named only decreased significantly. In addition, Cr-Mo steel,[link widoczny dla zalogowanych], heat treatment did not change the basic values of the base metal hardness, therefore, that For 1Cr5Mo steel welded joints, welding quality to ensure compliance in the premise, as long as the heat treatment temperature recorded curve qualified,[link widoczny dla zalogowanych], then the heat treatment quality standards at the same time, be pointed out that, for this example. from the effects of residual stress after welding to eliminate perspective, the joint should be with high current welding as well. (3) From Table 2,[link widoczny dla zalogowanych], Table 3 can be seen, due to the existence of specimen 6, the apparent lack of penetration weld defect, although the heat treatment temperature curve qualified, hardness qualified, non-joint microstructure abnormal state, residual stress effect is obvious, but the joints should return to work. This shows from another angle, the quality of welding joints attention should be paid, otherwise, even if the joint treatment of acceptable quality, but can not guarantee the performance and use of joint safe and reliable. Therefore, the stability of welding specifications,[link widoczny dla zalogowanych], qualified essential. shall ensure that post-weld 10t) testing inspection. 4 Conclusion 1Cr5Mo welded joints, the hardness of the maximum joint quality assessment index as a more appropriate treatment. Meanwhile, the premise of ensuring qualified welding quality, it can verify whether the heat treatment temperature recorded curve qualified or not qualified to judge the quality of heat treatment. References 1 Lu was good. Residual stress testing - the Hole Drilling Method. Xi'an: Xi'an Jiaotong University Press Du] 99160 Editor: Dong Honglin Received Date :1998-09-29
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