焊条的选用原则
Principle of the selection of electrode
（1）考虑焊缝金属的力学性能和化学成对于普通结构钢，通常要求焊缝金属与母材等强度，应选用熔敷金属抗拉强度等于或稍高于母材的焊条。对于合金结构钢有时还要求合金成分与母材相同或接近。在焊接结构刚性大、接头应力高、焊缝易产生裂纹的不利情况下，应考虑选用比母材强度低的焊条。当母材中碳、硫、磷等元索的含量偏高时，焊缝中易产生裂纹，应选用抗裂性能好的低氢型焊条。
(1) considering the mechanical properties of weld metal and chemical into for ordinary structural steel, usually requires the strength of weld metal and base, should choose deposited metal tensile strength equal to or slightly higher than that of parent metal electrode. Sometimes require for alloy structural steel alloy composition is the same as the parent metal or close to. In welding structure rigidity, high joint stress, weld crack generating adverse circumstances, should consider to choose lower than the strength of parent metal electrode. When the base of carbon, sulfur and phosphorus content on the high side when yuan, such as weld easy to produce cracks, should choose good low hydrogen type electrode crack resistance.
（2）考虑焊接构件的使用性能和工作条件：对承受动载荷和冲击载荷的焊件，除满足强度要求外，主要应保证焊缝金属具有较高的塑性和韧性，可选用塑、韧性指标较高的低氢型焊条。接触腐蚀介质的焊件，应根据介质的性质及腐蚀特征选用不锈钢类焊条或其他耐腐蚀焊条。在高温、低温、耐磨或其他特殊条件下工作的焊件，应选用相应的耐热钢、低温钢、堆焊或其他特殊用途焊条。
(2) : consider using performance of welded components and working conditions under dynamic load and impact load of weldment, in addition to meet the strength requirement, the main should guarantee the weld metal has higher plasticity and toughness, can choose plastic, high toughness index of the low hydrogen type electrode. Weldment of contact corrosion medium, should according to the nature of the medium and the corrosive characteristics of stainless steel electrode or other corrosion resistant electrode. In the high temperature, low temperature, abrasion, or other work under the special conditions of
weldment, should choose the corresponding heat resistant steel, low temperature steel welding rod, welding or other special purposes.
（3）考虑焊接结构特点及受力条件：对结构形状复杂、刚性大的厚大焊件，在焊接过程中，冷却速度快，收缩应力大，易产生裂纹，应选用抗裂性好、韧性好、塑性高、氢裂纹倾向低的焊条。如低氢型焊条、超低氢型焊条和高韧性焊条等。
(3) : welding structure characteristics and stress conditions on the structure of complex shape, large rigidity large and thick welding parts, in the process of welding, fast cooling and contraction stress is big, easy to produce cracks, should choose good crack resistance and good toughness, high plasticity, low hydrogen cracking tendency of the electrode. Such as the low hydrogen type electrode, low hydrogen type electrode and high toughness electrode, etc.
（4）考虑施焊条件：当焊件的焊接部位不能翻转时，应选用适用于全位置焊接的焊条。对受力不大、焊接部位难以清理的焊件，应选用对铁锈、氧化皮、油污不敏感的酸性焊条。没有直流焊机时，必须选用可交、直流两用的焊条。在狭小或通风条件差的场合，在满足使用性能要求的条件下，应选用酸性焊条或低尘焊条。
: welding conditions (4) considering when cannot reverse welding welding parts, should be chosen for all position welding electrode. To force is not big, the welding parts difficult to clean up the weldment, should choose is not sensitive to rust, scale, oil acid electrode. There is no dc welder, must choose ac, dc amphibious electrode. In small or poor ventilation condition, under the condition of meet the performance requirements, should choose acid electrode or low dust electrode.
（5）考虑生产效率和经济性：在酸性焊条和碱性焊条都可满足要求时，应尽量选用酸性焊条。对焊接工作量大的结构，有条件时应尽量选用高效率焊条，如铁粉焊条、重力焊条、底层焊条、立向下焊条和高效不锈钢焊条等。这不仅有利于生产率的提高，而且也有利于焊接质量的稳定和提高。
(5) considering the production efficiency and economical: electrode in acid and alkaline welding rod can meet the requirements, should try to choose acid electrode. The structure of welding workload big, conditional should try choosing electrode with high efficiency, such as iron powder electrode, gravity electrode and bottom electrode, vertical
down welding and high-performance stainless steel electrode, etc. This is not only beneficial to the improvement of productivity, but also conducive to the stability of welding quality and improve.