焊接的基本概念知识⑴熔化焊接（Fusion welding）手工电弧焊（SMAW：Shielded meta l arc weldi ng）埋弧焊（SAW：Submerged arc welding）钨极惰性气体保护电弧焊（TIG：Tungsten Inert-Gas arc welding）⑵压力焊接（Pressure welding）熔化极惰性气体保护电弧焊（MIG：meta l Inert-gas arc welding）爆炸焊（Expl osive welding）冷压焊（Cold welding）摩擦焊（Friction welding）扩散焊（Diffusion weldin g）焊缝接头（Welded joint）⑶钎焊（Soldering(软钎焊)/Brazing（硬钎焊））电阻钎焊（resistance brazing）火焰钎焊（torch brazing/ soldering）热压焊：hot pressure welding 电渣焊：electroslag welding薄钢板的焊接（We iling of thin steel sheets）电子束焊：electron beam welding 电阻焊：resistance welding 点焊: Spot w eld对接接头(Butt joint); 搭接接头（Lap joint）；角接接头（Fillet weld）T型接头（T-joint/Tee joint）最常用的是:对接接头（Butt joint is the most used one）不开坡口的对接接头（Butt joint without groove）两焊件端面相对平行的接头（The joint whose welding suefaces of both wel ding parts are parallel is called butt joint.）如果产品在厚度方向上不要求全焊透，可进行单面焊接，应必须保证焊缝的计算厚度H≥0.7δ，δ为板厚。
如果要求产品在整个厚度上全部焊透，可在焊缝背面用碳弧气刨清跟后再进行焊接，即形成不开坡口的双面焊接对接接头。
（If the product doesn’t need full penetration of welding, we can take single-si de welding, and must make sure that the caculating thickness is more than or equal to 0.7δ(δis the thickness of steel sheets),If full penetration of weld ing needed, we can use carbon arcgouging to back chipping at the back of weld, after which weiding can be taken, than the double-faced welding butt joi nt without groove is formed.）厚钢板的焊接（Weiling of thick steel sheets）开坡口的对接接头，用于钢板较厚而需要全焊透的焊件。
（Butt joint with groove is used for thick welding parts which is needed full penetration of welding）. 坡口的几何尺寸(Geometrical dimension of groove) 坡口（Groove）坡口面（Groove face/surface）焊件的坡口表面叫坡口面（The surface of groove is named groove face）1.2 坡口面的角度和坡口角度（groove face angle and groove angle）焊件表面的垂直面与坡口之间的夹角叫做坡口面角度（The angle between thevertical surface of the welding part and the groove is called groove face angl e.两个坡口之间的角度叫做坡口角度（The angle between the two groove faces is called gro ove face）.1.3 根部间隙（Root opening/clearance）在焊接前，接头根部之间留的预留的空隙叫根部间隙，根部间隙的作用在焊接打底焊道时，能保障根部可以焊透。
（The clearance obligated for joint before weldingis called root opning , whose function is to keep the root can be full penetrat ionwelded when backing weld is welded）.1.4 钝边（Root face）焊件开坡口时，沿焊件方向未开坡口的端面部分叫钝边。
（When groove is made,the face without groove along the weiding part direction is called root face）1.5 根部半径（Root radius）在J型、U型坡口底部的半径叫根部半径。
（The radius at the bottom of the J-groove or V-groove is called root radius）根据坡口形状的不同，长用的有：I型（不开坡口），V型，X型，U型；（For the different of groove shape, we can classify the groove mainly into I-groove(with out groove),v-groove,X-groove,U-groove.）V型坡口是最常用的坡口形式，便于加工，焊接时为单面焊，不用翻转焊件，但焊后容易变形。
（V-groove is the most used one.which is easy to machine and no turn is needed, but dis tortion is easy to form）氧气切割（oxygen cutting），碳弧气刨（carbonarcgouging），刨削（planing）车削（t urning）氧气切割：应用最广泛的一种，有手工、办自动、自动三种方法。
（oxygen cutting：The most used one,Inluding mannul,semi-automatic and automatic opera tion.）焊缝（weld）1. 焊缝的分类：对接焊缝（butt weld）,角焊缝（fillet weld）,塞焊缝（plug weld），2.1 焊缝尺寸：焊缝的尺寸用一系列几何尺寸来表示：weld dimension:（The dimension of weld is defined by a series of geometrical dimensi ons.）⑴焊缝宽度（weld width）⑵余高（weld reinforcement）⑶熔深（depth of penetration）⑷焊缝厚度（weld depth）⑸角焊缝的形状和尺寸（The shape an dimension of fillet joint）：①焊缝计算高度（weld caculating hight）②焊缝凸度（weld convexity）③焊缝凸度（weld concavity）⑹焊缝成型系数（The coefficient of weld moulding焊接工艺参数对焊缝成型的影响（The affection of welding procedure parameter to weld formation）焊接工艺参数：焊接时，为保证焊接质量而选定的诸物理量（如：焊接电流、电弧电压、焊接速度、线能量等）的总称叫焊接工艺参数。
（Welding procedure parameter：The floorboard of all physical terms(as weiding current,arc voltage,welding speed, energy definitions and so on)which are selec ted to ensure the welding quality when welding is taken is called welding proce dure parameter）1、焊接电流：当其它条件不变时，增加焊接电流，则焊缝宽度和余高都增加，而焊缝宽度几乎保持不边。
其原因是：Welding current:When the other conditions don’t change, if the weld current is added,both the weld depth and weld reinforcement will increase, the weld width almost will not change. The reasons are:⑴焊接电流增加时，电弧的热量增加，因此熔池体积和弧坑深度都随电流增加，所以冷却下来后，焊缝厚度就增加。
When the welding current is added, the quality of heat of the arc will increa se, so both the volume of molten puddle and the depth of arc crater will all in crease, and the weld depth will increase when the weld is cooling.⑵焊接电流增加时，焊丝的熔化量也增加，因此焊缝的余高也随之增加。
When the welding current is added, the fusion quality of welding stick will in crease, so the weld reinforcement also will increase.⑵焊接电流增加时，一方面是电弧截面略有增加，导致熔宽增加，另一方面是电流增加促使弧坑深度增加。