Introduction to common Welding consumables
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1. Concept of Welding consumables
Welding consumables are various materials used in welding processes, including welding metals, welding electrodes, welding auxiliary materials, etc. These materials play different roles in the welding process, such as providing strength, electrical conductivity, thermal conductivity, corrosion resistance, etc. Common Welding consumables include: welding metal, welding electrodes, welding auxiliary materials, welding filler materials, welding additives, and welding protective agents.
2. The harmfulness of Welding consumables
(1) The main research object of welding labor hygiene is fusion welding, among which open arc welding has the greatest labor hygiene problems, and submerged arc welding and electroslag welding have the least problems.
(2) The main harmful factor in manual arc welding with coated electrodes, carbon arc gouging and CO2 gas shielded welding is the fume generated during the welding process – electric welding fume. Especially arc welding. and carbon arc gouging. If the welding operation is performed in a narrow working space environment (boiler, cabin, closed container and pipeline, etc.) for a long time, and if the health protection is not good, it will cause harm to the respiratory system, etc., and in severe cases, it is easy to Suffering from welding pneumoconiosis.
(3) Toxic gas is a major harmful factor in gas electric welding and plasma arc welding. When the concentration is relatively high, it will cause poisoning symptoms. Among them are ozone and nitrogen oxides, which are produced by arc high-temperature radiation acting on oxygen and nitrogen in the air.
(4) Arc radiation is a common harmful factor in all open arc welding, and the electro-optical eye disease caused by it is a special occupational disease in open arc welding. Arc radiation can also damage the skin, causing welders to suffer from skin diseases such as dermatitis, erythema and small blisters. In addition, cotton fibers can be damaged.
(5) In tungsten arc welding and plasma arc welding, since the welding machine is equipped with a high-frequency oscillator to help start the arc, there are harmful factors – high-frequency electromagnetic fields, especially welding machines with long working hours of high-frequency oscillators (such as Some factory-made argon arc welding machines). High-frequency electromagnetic fields can cause welders to suffer from diseases of the nervous system and blood system.
Due to the use of thoriated tungsten rod electrodes, thorium is a radioactive substance, so there are harmful radiation factors (α, β and γ rays), which may cause radioactive hazards around the grinder where the thorium tungsten rod is stored and sharpened.
(6) Plasma arc welding, spraying and cutting produce strong noise, which can damage the welder’s auditory nerve if the protection is not good.
(7) The main harmful factors during gas welding of non-ferrous metals are oxide dust and smoke formed by evaporation of molten metal in the air, and toxic gases from the flux.
3. Types of Welding consumables
(1) Degreasing agent
Cleaning the metal to be welded with a degreaser will help make the weld stronger. Grinding or filing a bevel along the edge of the weld will help the liquid metal penetrate deeply into the joint. Clean the weld with light grinding or filing. Do not Excessive welding will damage the weld.
(2) Electrode
The electrode tool transfers electric current from the welding machine to the material being welded, heating it and turning it into a liquid. The electrode head is made of non-consumable tungsten. Due to the uneven or weak shape of the weld, some welds need to be fed to strengthen the joint, and the welding rod Feed wire using electrode feed.
(3) Angle grinder
Use an angle grinder to help smooth joints and clean metal surfaces before welding.
(4) Welding rod furnace
Welding furnaces are basic Welding consumables used to store welding rods or to continuously heat welding rods.
(5) Electrode holder
Two copper wire cables covered with tough insulation carry current from and back to the welding machine, requiring an electrode holder that is lightweight, insulated and durable enough to withstand the wear and tear of continuous operation.
(6) Ground clamp
Ground clamps are used to connect ground cables to the workpiece or welding station, requiring a cable gland to connect the cable to the machine.
(7) Safety equipment
Welding is very dangerous due to excessive temperatures and can be fatal if not handled properly. Before handling welding consumables and equipment, wear a helmet with eye protection, ear plugs, solid boots to protect feet from sparks or slag, glove protection, and leather Cover other parts of the body.
(8) Protective equipment
A welding mask protects the face and eyes from electric rays and molten metal splash, held with one hand while welding with the other, other materials include a chisel hammer, wire brush, safety glasses for cutting welds, vice clamps , anvil, hammer, pliers.
(9) Welding rod
A welding rod is a coated, molten electrode used in arc welding. It consists of two parts: coating and welding core.
①Welding core. The metal core covered by the coating in the welding rod is called the welding core. The welding core is generally a steel wire with a certain length and diameter. When welding, the welding core has two functions: first, it conducts the welding current and generates an arc to convert electrical energy into heat energy; second, the welding core itself melts into filler metal and fuses with the base metal to form a weld.
Special steel wires used for welding can be divided into three categories: carbon structural steel wires, alloy structural steel wires and stainless steel wires.
②Medicine skin. The coating applied on the surface of the solder core is called coating. Coating a layer of coating composed of various minerals on the outside of the light welding rod can stabilize the arc combustion and improve the quality of the weld.
Some reducing agents should be added to the coating to reduce the oxides to ensure the quality of the weld.
Due to the high temperature of the arc, some alloy elements contained in the weld metal are burned (oxidized or nitrided), which will reduce the mechanical properties of the weld. By adding iron alloy or pure alloy elements to the electrode coating, they transition to the weld metal as the coating melts to compensate for the burning loss of the alloy elements and improve the mechanical properties of the weld metal.
Improve the welding process performance to achieve stable arc combustion, less spatter, good welding seam shape, easy slag removal and high deposition efficiency.
In short, the function of the coating is to ensure that the weld metal has the required chemical composition and mechanical properties, and to enable the electrode to have good welding process performance.
(10) The main Welding consumables for oxygen cutting are:
Cutting nozzle, oxygen welding gun, oxygen cutting nozzle, flux, base material (covered by Welding consumables), welding gloves, protective mask, etc.
The main application industries are metal sheet industry, medical equipment industry, mold making, furniture factory, bicycle moped industry, boat parking industry… It can be said that it is used in various industries.
4. Precautions for Welding consumables
(1) Substrate properties and matching:
Determine the chemical composition, hardness, strength, toughness and thermal expansion coefficient of the base material to be welded.
Understand the required mechanical properties and corrosion resistance of welded joints to ensure that the selected welding consumables match the base material and can meet the usage requirements of the welded joint.
(2) Welding consumables characteristics:
For welding metals (Welding consumables), consider their melting point, thermal conductivity, electrical conductivity, thermal expansion coefficient and chemical inertness.
For welding electrodes and filler materials, know their chemical composition, welding properties (melting characteristics, wettability), tendency to form pores, and mechanical properties such as strength and hardness.
(3) Welding process and conditions:
Determine the welding method (such as manual welding, automatic welding, semi-automatic welding) and welding process (such as arc welding, gas shielded welding, laser welding).
Select appropriate welding materials according to the welding process to ensure that they can provide stable welding performance under the selected process conditions.
(4) Welding joint design:
Consider the design and geometry of the weld joint to determine the best welding material selection and filler material form (e.g., electrode, wire, powder).
According to the structure, thickness and shape of the welded joint, the welding parameters and material selection are adjusted to ensure the quality and reliability of the welded joint.
(5) Welding quality control:
Implement quality control measures during the welding process, such as preheating, welding interpass temperature control, welding speed control, and post-heat treatment.
Conduct non-destructive testing (such as X-ray testing, ultrasonic testing) and destructive testing on welded joints to ensure that the welded joints meet the specified quality standards and performance requirements.
(6) Environmental and safety considerations:
Take necessary safety measures during welding, such as wearing protective glasses, gloves and face shields, and providing a good ventilation system.
Ensure that the storage and handling of Welding consumables comply with safety regulations to avoid safety issues caused by improper storage or misuse.
(7) Suppliers and quality control:
Choose a reliable welding materials supplier to ensure that its products meet quality standards and certification requirements.
Implement supply chain management and quality control to ensure that the selected welding materials have reliable sources, stable quality, and can meet production needs.
In the welding process, it is crucial to select appropriate Welding consumables, which directly affects the quality, stability and reliability of the welded joint. We need to comprehensively consider various aspects such as base material properties, welding methods, welding conditions, safety and environmental protection, etc. to ensure that the selected Welding consumables can meet the process requirements and ensure the quality of the welded joints. In addition, welding quality control and supplier management are also important steps to ensure the quality stability of welding materials.
In practical applications, we need to pay close attention to various details in the selection, use and handling of Welding consumables to ensure the safety, efficiency and reliability of the welding process. At the same time, we continue to learn and master new welding materials and process technologies, actively adopt advanced welding materials and methods, and continuously improve welding quality and production efficiency.
In summary, the selection and use of Welding consumables requires comprehensive consideration of multiple factors and continuous improvement and improvement in practice to ensure the quality and stability of the welding process and provide reliable support for the successful implementation of various engineering projects. Welding support.
