Question 2: What are the common arc welding welding methods? What are the characteristics of each? Common electric welding welding methods are 1, manual arc welding: the use of electric arc as a heat source to melt the electrode and the base material to form a weld hand-operated welding method, the arc temperature in 6000-8000 ℃ or so. Applicable to ferrous metals and some non-ferrous metal welding, a wide range of applications, especially for short welds, irregular welds. 2, submerged arc welding: (sub automatic, semi-brake) arc in the flux area under the combustion, the use of granular flux, as a cover layer of the molten metal pool, will be isolated from the air so that it shall not enter the molten pool. Welding wire is continuously fed into the arc zone by the wire feeding mechanism, and the welding direction and moving speed of the arc are completed manually or mechanically. Suitable for medium and thick plate materials such as carbon steel, low alloy steel, stainless steel, copper and other straight weld and rule weld welding. 3, gas welding: (gas shielded welding and argon arc welding) the use of shielding gas to protect the welding zone of the arc welding. Shield gas as a protective layer of the molten metal pool to isolate the air. The use of gas inert gas, reducing gas, oxidizing gas for carbon steel, alloy steel, copper, aluminum and other non-ferrous metals and their alloys welding. Oxidizing gases are suitable for carbon steel and alloy steel alloys 4, ion arc welding: the use of gas ionization in the arc, and then after the thermal contraction effect, mechanical contraction effect, magnetic contraction effect of a super-high-temperature heat source for welding, the temperature can reach about 20,000 ℃.
Question 3: What are the three more common daily welding methods? Daily more common welding methods are, focusing on daily: argon arc welding (such as stainless steel doors and windows production and installation, etc.), welding rod arc welding (such as automobile, electric car, bicycle repair department, etc. are useful to), brazing (electrical repair department of the circuit board welding, that is, soldering iron soldering, etc.), and heat welding (now renovation and installation of water intake pipe with).
Question 4: There are several methods of welding metal welding method has more than 40 kinds, mainly divided into fusion welding, pressure welding and brazing three categories.
Melt welding is in the welding process will be heated to the melting state of the workpiece interface, do not add pressure to complete the welding method. Melt welding, the heat source to be welded two workpiece interface quickly heated melting, forming a molten pool. The molten pool with ...
Melt welding is in the welding process will be heated to the melting state of the workpiece interface, do not add pressure to complete the welding method. Welding, the heat source will be welded to the two workpiece interface quickly heated and melted to form a molten pool. The molten pool with the heat source to move forward, after cooling to form a continuous weld and the two workpieces connected to become one.
In the welding process, if the atmosphere and the high temperature of the molten pool in direct contact, the oxygen in the atmosphere will oxidize the metal and various alloying elements. Atmospheric nitrogen, water vapor, etc. into the molten pool, but also in the subsequent cooling process in the weld to form pores, slag, cracks and other defects, deteriorating the quality and performance of the weld.
In order to improve the quality of welding, people have developed a variety of protection methods. For example, gas shielded arc welding is to use argon, carbon dioxide and other gases to isolate the atmosphere to protect the welding arc and molten pool rate; another example of steel welding, in the electrode flux skin to add the oxygen affinity of titanium and iron powder deoxygenation, you can protect the electrode from oxidation of beneficial elements such as manganese, silicon and so on into the molten pool, cooled to obtain a high-quality weld.
Pressure welding is in the pressurized conditions, so that the two workpieces in the solid state to achieve inter-atomic bonding, also known as solid-state welding. Commonly used pressure welding process is resistance welding, when the current through the two workpieces connected to the end, the place due to the resistance of the temperature rises, when heated to the plastic state, in the axial pressure under the action of the connection becomes one.
Various methods of pressure welding *** with the same characteristics of the welding process to apply pressure without adding filler material. Most of the pressure welding methods such as diffusion welding, high-frequency welding, cold pressure welding, etc. There is no melting process, so there is no beneficial alloying elements such as melt welding burned, and harmful elements into the weld, thus simplifying the welding process, but also to improve the welding safety and health conditions. At the same time, due to the heating temperature is lower than the melt welding, heating time is short, so the heat-affected zone is small. Many difficult to weld with fusion welding materials, often can be welded with pressure welding into a high-quality joints with the same strength as the base material.
Brazing is the use of metal materials than the melting point of the workpiece as a brazing material, the workpiece and brazing material heated to a temperature higher than the melting point of the brazing material, lower than the melting point of the workpiece, the use of liquid brazing material to wet the workpiece, fill the gap between the interface and workpiece to achieve the mutual diffusion of the atoms, so as to achieve the welding method.
The joint formed when welding connects the two connected bodies is called a weld. Both sides of the weld in the welding will be subjected to welding heat, and organization and performance changes, this region is called the heat affected zone. Welding due to the workpiece material welding material, welding current, etc., after welding in the weld and heat-affected zone may produce overheating, embrittlement, quenching or softening phenomenon, but also to make the performance of the weldment decreased, deteriorating weldability. This requires adjusting the welding conditions, pre-welding on the weldment interface preheating, welding insulation and post-welding heat treatment can improve the welding quality of the weldment.
In addition, welding is a localized rapid heating and cooling process, the weld zone due to the constraints around the body of the workpiece can not be free to expand and contraction, cooling in the weldment will produce welding stress and deformation. Important products need to eliminate welding stress after welding, correction of welding deformation.
Modern welding technology has been able to weld without internal and external defects, mechanical properties equal to or even higher than the weld to be connected to the body. Welded body in the space of the mutual position known as welded joints, the strength of the joints in addition to the impact of the quality of the weld, but also with its geometry, size, stress and working conditions. The basic forms of joints are butt, lap, butyl joint (orthogonal joint) and angle joints.
The cross-sectional shape of the butt joint weld is determined by the thickness of the welded body before welding and the form of the bevel of the two edges. Welding thicker steel plate, in order to weld through the edge of a variety of shapes of beveling, in order to more easily feed the electrode or wire. The bevel form has a single-side welding bevel and two-side welding bevel. Selection of bevel form, in addition to ensuring that the weld penetration should also consider the convenience of welding, less filler metal, welding deformation and low bevel processing costs and other factors.
Thickness of the two steel plate butt joints, in order to avoid rapid changes in the cross-section caused by severe stress concentrations, often the thicker side of the plate is gradually thinned, to achieve the two edges of the joint at the same thickness. The static and fatigue strength of butt joints is higher than that of other joints. In the alternating, impact load or in the low temperature and high pressure container work in the joint, often prioritize the use of butt joints welding.
The pre-weld preparation of lap joints is simple, ...... >>
Question 5: What are the commonly used welding methods for stainless steel Hello, almost all welding methods can be used to weld stainless steel, although because of the different types of stainless steel and different. Currently commonly used stainless steel melting welding methods include manual arc welding, submerged arc automatic welding, tungsten inert gas shielded welding, fused pole gas shielded welding, plasma arc welding, etc. In addition, electron beam welding and laser welding are sometimes used.
(1) Manual Arc Welding
Manual Arc Welding is a welding method of manual operation arc welding electrode welding. Manual arc welding, the use of welding rod and workpiece arc between the welding rod and workpiece local heating to a molten state, the end of the welding rod melted droplets and melted base material fused together to form a molten pool, with the arc moving forward, the molten pool of liquid metal gradually cooled to form a weld crystallization. Manual arc welding of stainless steel, the most widely used, can be used for all types of stainless steel welding. It is characterized by manual arc welding heat-affected zone is small, easy to ensure quality, simple equipment, flexible operation, to adapt to a variety of welding positions and different plate thickness process requirements. Now, the stainless steel electrode can basically meet the welding requirements of various types of stainless steel, welding rod selection is almost unrestricted.
Disadvantages are low productivity; poor labor conditions; higher requirements for welders, on many occasions, the welder must have considerable qualifications; some of the materials welded deposited metal is not up to the use of the requirements, such as ultra-high purity stainless steel; the workpiece thickness is generally less than 1mm of thin plate is not suitable for manual arc welding.
(2) submerged arc automatic welding is the welding arc with a layer of granular melting flux covered underneath. Arc light is not exposed to a welding method. At present, it is mainly used for welding austenitic stainless steel medium-thick plate, which is characterized by a large welding current, large depth of fusion, the bevel of the workpiece can be smaller; welding speed, high productivity; slower solidification of the weld metal, the liquid metal and the melted flux have more time for metallurgical reaction, reducing the possibility of porosity in the weld; weld shaping beautiful, good working environment, easy to operate, the requirements of the welder is relatively simple.
Disadvantages
The disadvantage is that the welding heat input is large, the heat-affected zone is wide, the weld organization is coarse; the selection of materials should be especially considered when the wire and flux with; welding position can only be flat welding position; can not directly observe the arc and bevel relative position, there must be automatic tracking device.
(3) tungsten inert gas shielded welding
Tungsten inert gas shielded welding (English abbreviation TIG welding) can be divided into manual welding, semi-automatic welding and automatic welding of three kinds. tungsten argon arc welding in the TIG welding in
stainless steel in the application is quite common. It is adapted to all-position welding, generally does not produce spatter, and the weld is beautifully shaped. Especially adapted to the welding of thin parts, in many thick parts of the bevel welding, commonly used GIG bottoming, to avoid the manual electric
Arc welding is prone to cracks and slag clearing difficult shortcomings. Inert gas can effectively isolate the air, it itself is insoluble in metal, not and metal reaction, can ensure that the chemical composition of stainless steel requirements.
The disadvantage is that the melting depth is shallow, the melting speed is small, the production efficiency is low, and the production cost is high.
(4) melting electrode gas shielded welding
The melting electrode gas shielded arc welding (GMAW) uses a melting wire and the welded workpiece between the arc as a heat source to melt the wire and the base metal, and to the welding zone to deliver protective gas, so that the arc, the melted wire, the molten pool
and the nearby base metal from the surrounding air infringement. The continuously fed wire metal continues to melt and transition to the molten pool, fusing with the molten base metal to form the weld metal, thus interconnecting the workpieces. Melting electrode gas
Shielded welding can be automatic welding, can also be semi-automatic welding.
The fused electrode gas shielded welding is divided into fused electrode inert gas shielded welding (MIG), fused electrode oxidizing mixed gas shielded welding (MAG), CO2 gas shielded welding and flux cored wire gas rest protection welding.
Melting pole inert gas shielded welding (MIG) in the welding of stainless steel is more commonly used, usually using inert gases of argon, helium, or a mixture of them as the welding zone of the shielding gas, due to the appearance of the wire is not coated
layer, the current can be greatly increased, and thus the base material depth of fusion is large, the wire melts fast, high deposition rate, compared with tungsten argon arc welding, can greatly improve the productivity. Production efficiency. Especially suitable for welding medium-thick plate.
(5) plasma arc welding
The plasma arc is a compression arc, due to the arc section is compressed smaller, and thus the energy concentration, high temperature, high flame flow rate, so the plasma arc welding in a certain range of thickness of the base material can be fully penetrated, especially suitable for stainless steel pipe
longitudinal seam welding. Plasma arc welding welding speed faster than TIG welding, arc straightness is good, the size of the heat impact, can ...... >>
Question 6: What are the forms of welding? The above answer is only the code name of the welding method is not the form of welding, in fact, it should be the welding method.
Welding is the process of obtaining the formation of integral joints with the help of inter-atomic links and diffusion between protons. It can also be considered that welding is the use of heat or mechanical pressure, or both, the use of filler material, two or more workpieces connected together, become inseparable solid joint method.
1, the way of welding
First, fusion welding
is the welding process, the weldment joints will be heated to a molten state, not pressurized to complete the welding method. In the heating conditions to enhance the kinetic energy of the metal atoms, promote mutual diffusion between the atoms, when the welded metal heated to the melting state to form a liquid melt pool, the atoms can be fully diffused and close contact, so the cooling and solidification, that is, the formation of solid welded joints (can be used as an analogy to ice). Common gas welding, arc welding, electroslag welding, gas-shielded welding, etc. belong to the welding method.
Second, pressure welding
is the welding process must be applied to the weldment pressure (heated or unheated), in order to complete the welding method. There are two forms of such welding, one is the welded metal contact part of the heating to the plastic state or local melting state, and then apply a certain amount of pressure in order to make the metal atoms combined with each other to form a solid welded joints, such as forging, contact welding, friction welding and pneumatic welding is this pressure welding method. The second is not heated, only in the contact surface of the welded metal to apply sufficient pressure, with the help of plastic deformation caused by the pressure, in order to get close to each other between the atoms and obtain a solid joint, this method has a cold pressure welding, explosive welding, etc. (mainly used for composite steel plate).
Third, brazing
is the use of low melting point than the base material of metal materials, welding and brazing material heated to higher than the melting point of brazing material, lower than the melting point of the base material of the temperature, the use of liquid brazing material to wet the base material, fill the gap between the joints and diffusion of the base material to achieve the method of jointing the weldments. Common brazing methods are soldering iron welding, flame brazing.
2, welding methods
First, welding
1, gas welding:
The use of oxyacetylene or other gases flame heating base material and filler metal, to achieve the purpose of welding. Flame temperature of about 3000 ℃. Applicable to thinner workpieces, small diameter pipes, non-ferrous cast iron, brazing.
2, manual arc welding:
The use of electric arc as a heat source to melt the electrode and the base material to form a weld manually operated welding method, the arc temperature of 6000-8000 ℃ or so. Applicable to ferrous metals and some non-ferrous metal welding, a wide range of applications, especially for short welds, irregular welds.
3, submerged arc welding:
(sub automatic, semi-brake) arc in the flux area under the combustion, the use of granular flux, as a cover layer of the molten metal pool, will be isolated from the air so that it shall not enter the molten pool. The wire is continuously fed into the arc area by the wire feeding mechanism, and the welding direction and moving speed of the arc are completed manually or mechanically.
It is suitable for the welding of straight and regular welds of carbon steel, low alloy steel, stainless steel, copper, etc. of medium and thick plate materials.
4 gas welding:
(gas shielded welding) the use of shielding gas to protect the welding zone of the arc welding. Shield gas as a protective layer of the molten metal pool to isolate the air. The use of gas inert gas, reducing gas, oxidizing gas is suitable for carbon steel, alloy steel, copper, aluminum and other non-ferrous metals and their alloys welding. Oxidizing gases are suitable for carbon steel and alloy steel alloys
5, ion arc welding:
The use of gas ionization in the arc, and then after the thermal contraction effect, the mechanical contraction effect, the magnetic contraction effect of an ultra-high-temperature heat source for welding, the temperature can reach about 20,000 ℃.
Second, pressure welding
1, friction welding:
The use of friction between the weldments each other, the heat generated by the rotation of the contact end face, the application of a certain amount of pressure and the formation of welded joints. Applicable to aluminum, copper, steel and dissimilar metal materials welding.
2, resistance welding:
The use of electric current through the weldment produced by the resistance of the heat, heating the weldment (or the base material) to the plastic state, or local melting state, and then apply pressure to make the weldment connected together. Suitable for welding thin plates, tubes, bars.
Third, brazing
1, soldering iron brazing:
The use of electric soldering iron or flame heating soldering iron heat. Heating the parent material localized, and make the filler metal melted into the gap, to achieve the purpose of connection. Applicable to the melting point of 300 ℃ brazing material. Generally used for wires, circuit boards and original welding.
2, flame brazing:
The use of gas flame as a heating source, heating the base material, and filler metal material melted into the gap, to achieve the purpose of the connection is applicable to, stainless steel, hard alloys, non-ferrous metals, and other general size of the smaller weldments.
3, the classification of welding methods
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Question 7: What are the common methods of pipe welding Welding methods are divided into: manual arc welding, oxyacetylene welding, tungsten grade argon arc welding, fusion electrode argon arc welding, carbon dioxide shielded welding, submerged arc welding
Welding position is divided into: flat welding, vertical welding, transverse welding or vertical fixation welding, backward welding, pipe horizontal fixation welding, tube 45 ° tilt fixation welding, pipe horizontal rotation welding.
Question 8: What are the common tools used for welding 1) Soldering iron
Soldering iron is a necessary tool for welding, used to raise the temperature to make the tin melt.
The soldering iron consists of a heating core, an insulated handle and a soldering iron tip. After electricity passes through the current, a resistance heating element generates heat. Portable soldering irons can be heated with a small can of gas, usually with a catalytic heater rather than a flame.
Soldering irons are often used in electronics assembly for installation, repair, and small amounts of production work. Other welding methods are used for large production lines. Large soldering irons can be used to weld thin metal objects.
Soldering irons can be categorized as low-temperature, high-temperature, and thermostatic. Depending on the performance, the price varies.
2) Soldering Furnace
Soldering Furnace, is a small, temperature-controlled furnace or container, flared mouth, used for tinning wires and soldering iron tip tin. Tin furnace to melt tin, dip soldering small circuit boards, wires on the tin, soldering iron tip heavy on the tin, etc. particularly useful. Tin furnace in the requirements must have reliable temperature control of small-scale work is particularly useful.
3) Solder
Soldering materials are essential to the production and maintenance of the electronics industry, in general, the commonly used soldering materials are tin-lead alloy solder, plus antimony solder, plus cadmium solder, plus silver solder, plus copper solder.
The main products of solder are divided into three categories: solder wire, solder bars, solder paste. Used in various types of electronic welding, suitable for manual welding, wave soldering, reflow soldering and other processes. Classification: leaded solder, lead-free solder
4) Wire Strippers
Used to quickly strip the insulation of the head of the wire
5) Scissors
Used to cut off the parts, components, excess pins, wires, or plastics
6) Vise grips
Used to fix, clamp or locate the parts, circuit boards.
7) Suction wire
Desoldering.
Suction wire is a specialized repair tool that greatly reduces rework/repair time on electronic products and greatly reduces the risk of thermal damage to the circuit board. The precise geometry of the braid design ensures maximum surface tension and tin suction capability.
8) Fluxes
Chemicals that assist and facilitate the soldering process while protecting against oxidation. Types of fluxes:
1. water-soluble flux 2. no-clean flux 3. rosin flux
9) Water
Used for cleaning, wetting sponges.
10) Acid Resistant Brush
Usually used to clean flux paste containing lead.
11)Industrial Alcohol
Used for pre-soldering and post-soldering cleaning components, parts or circuit boards.
Question 9: What are the common welding methods for steel structure If the plant inside the production of I-beams generally use submerged arc welding, small parts are made with gas welding or electrode welding.
Outside the installation, the electrode welding is used more.
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Question 10: What are the commonly used welding methods for steel structure Welding of steel structure is mainly based on arc welding welding methods, electrode arc welding, submerged arc welding, carbon dioxide welding and argon arc welding, etc., and on some occasions there are gas welding and gas cutting, etc.
The welding of steel structure is mainly based on arc welding methods, electrode arc welding, submerged arc welding, carbon dioxide welding and argon arc welding.