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低温钢焊条的选用低温钢按使用温度不同分为-40、-70、-100、-196和-253℃等级,焊接时选用的焊条见表13。低温钢按组织特点可分为两大类,一是用于-40～-100℃的低碳铁素体-珠光体类;二是用于-196～-253℃的奥氏体类。低温钢具有比较好的焊接性能。为获得与母材相同低温性能的接头,通常采用小电流多道快速焊,并控制层间温度≤200～300℃。低温钢焊接结构应有很高的抗裂性能,所以低温钢焊条需控制氢含量。对TW40-7、TW70-7焊条要求扩散氢含量[H]≤6毫升/100克,对TW105-7焊条
The selection of low temperature steel electrode Low temperature steel according to the use of temperature is divided into different levels -40, -70, -100, -196 and -253 ℃, welding electrode selection table 13. Low-temperature steel can be divided into two categories according to the characteristics of the organization, one for the low-carbon ferritic-pearlite class from -40 to -100 ° C and the second for the austenite range from -196 to -253 ° C. Low temperature steel has better welding performance. In order to obtain the same low temperature performance with the base metal fittings, usually using small current multi-channel rapid welding, and control the temperature between layers ≤ 200 ~ 300 ℃. Low temperature steel welding structure should have a high crack resistance, low temperature steel electrode to control the hydrogen content. TW40-7, TW70-7 electrode requirements diffusion of hydrogen content [H] ≤ 6 ml / 100 grams of TW105-7 welding rod