【文章內(nèi)容簡(jiǎn)介】 牌號(hào) E4303 J422 鈦鈣型 E5015 J507 低氫鈉型 E5016 J506 低氫鉀型 表 1 6 碳鋼焊條的型號(hào)及其含義（ G B / T51 17 1995 ） 焊條型號(hào) 藥皮類(lèi)型 電源種類(lèi) 焊接位置 熔敷金屬 抗拉強(qiáng)度 E 4 3 0 0 特殊型 交流或直流 平焊、立焊、仰焊、橫焊 ≥ 4 2 0 MP a E 4 3 0 1 鈦鐵礦型 E 4 3 0 3 鈦鈣型 E 4 3 1 0 高纖維素鈉型 直流反接 E 4 3 1 1 高纖維素鉀型 交流或直流反接 E 4 3 1 2 高鈦鈉型 交流或直流正接 E 4 3 1 3 高鈦鉀型 交流或直流 E 4 3 1 5 低氫鈉型 直流反接 E 4 3 1 6 低氫鉀型 交流或直流反接 E 4 3 2 0 氧化鐵型 交流或直流 平焊 交流或直流正接 平角焊 E 4 3 2 2 平焊（適宜單道焊） E 5 0 0 1 鈦鐵礦型 交流或直流 平焊、立焊、仰焊、橫焊 ≥ 4 9 0 MP a E 5 0 0 3 鈦鈣型 E 5 0 1 0 高纖維素鈉型 直流反接 E 5 0 1 1 高纖維素鉀型 交流或直流反接 E 5 0 1 4 鐵粉鈦型 交流或直流 E 5 0 1 5 低氫鈉型 直流反接 E 5 0 1 6 低氫鉀型 交流或直流反接 E 5 0 1 8 鐵粉低氫鉀型 The principles of electrode selection: ① the metal to be welded, ② the property of the weld, ③ the working conditions, ④ the shape and thickness of the workpiece, ⑤ welding position, and ⑥ cost. Shielded MetalArc Welding equipment electrode holder 焊把，電極夾 cable 電纜 welding machine 焊機(jī) power source 電源 Figure Schematic illustration of the shielded metalarc welding operations (also known as stick welding, because the electrode is in the shape of a stick). Power source: 1. The current may be DC or AC (50A～ 300A). 2. The polarity of the DC current: ① straight polarity : the workpiece is positive and the electrode negative. It produces shallow peration, and is good for joints with very wide gaps. ② reverse polarity : The electrode is positive. Deeper weld peration is possible. 3. The AC method: the arc pulsates rapidly。 this method is suitable for welding thick sections and for using largediameter electrode at maximum currents. Process capabilities ① It is simple, portable and versatile (簡(jiǎn)單、靈活、適應(yīng)面廣） . It is monly used in general construction（建筑） , in shipbuilding（造船） , on pipelines（管道） and for maintenance（維護(hù)） work. ② The cost of equipment is low . ③ It can be used with most ferrous and nonferrous metals (319mm). For thicker plate (slag removed before next pass) Fig A deep weld showing the buildup sequence of individual weld sequence. Submerged Arc Welding— SAW 埋弧焊 Process and equipment: The weld arc is generated between the electrode and workpiece, and it is shielded by a granular flux, consisting of lime（石灰石） , silica（硅酸鹽） , manganese oxide（氧化錳） , calcium fluoride(氟化鈣） , and other pounds. The flux is fed into the weld zone by gravity flow through a nozzle. reel 盤(pán) wirefeed 送絲 contact tube 導(dǎo)電嘴 recovery 回收 hopper 斗 weld backing 焊接襯墊 Function of the flux (unfused flux): (焊劑） The thick layer of flux pletely covers the molten metal. It prevents spatter and sparks and suppresses the intense ultraviolet radiation and fumes characteristic of the SMAW process. The flux takes part in the metallurgical reactions at high temperature. Alloying element in flux can be effectively transfer to the weld metal to enhance the properties of the joint. The flux also acts as a thermal insulator, promoting deep peration of heat into the workpiece. Electrode: (焊絲，電極） The consumable electrode is a coil of bare round wire in diameter. It is feed automatically through a contact tube （導(dǎo)電嘴） . Process capabilities ? The SAW process is limited to welds in a flat or horizontal position and having a backup piece. Straight long welds and circular welds can be made. ? The quality of the weld is very high, with good toughness, ductility, and uniformity of properties. ? It provides very high welding productivity (I=300A～ 2023A), depositing 410 times the amount of weld metal per hour as the SMAW process。 ? It is used to weld a variety of carbon and alloy steel and stainless steel sheet or plate (﹥ 1mm), often at speeds as high as 5m/min. Typical applications include thick plate welding for shipbuilding and for pressure vessels. Multiple electrode Gas MetalArc Welding (GMAW) 熔化極氣體保護(hù)焊 ? Gas ? MetalArc welding Fusion Brazing and soldering Solid state Chemical Electrical Electrical Chemical Mechanical Shielded MetalArc Submerged Arc Plasma Arc Gas MetalArc FluxCored Arc Gas TungstenArc ElectronBeam LaserBeam Electrogas Electroslag Atomic Hydrogen et al Gas metalarc welding (GMAW), developed in the 1950s, is formerly called metal inertgas welding or metal activegas welding (MIG/MAG)（ 熔化極惰性氣體保護(hù)焊 / 活性） . The weld arc is generated between the electrode and workpiece. The weld area is shielded effectively by an atmosphere of argon, helium, carbon dioxide, or various other gas mixtures. The consumable bare wire is fed automatically through a nozzle into the weld arc. As an addition to the use of inert shielding gases, deoxidizers （脫氧劑） are usually present in the electrode metal itself, in order to prevent oxidation of the molten weld puddle （ 熔池） . (1) Principle Solid wire 實(shí)芯焊絲 Electrode 電極 Shielding gas 保護(hù)氣 Contact tube 導(dǎo)電嘴 Nozzle 噴嘴 Base metal 母材 Fig. Schematic illustration of GMAW process (2) Equipment Power source 電源 Wire feeder 送絲機(jī) Gas supply system 供氣系統(tǒng) Fig. Equipment for GMAW (3) Types of GMAW Gas ① Metal inertgas welding (MIG) 熔化極惰性氣體保護(hù)焊 Shielding gas: argon（氬氣） , helium（氦） It is mainly used for the welding of stainless steel and nonferrous metals （有色金屬） . ② Metal activegas welding (MAG) 熔化極活性氣體保護(hù)焊 gas mixtures: Ar + O2 or Ar + CO2 and more It is mainly used for th