Arc welding is a safe occupation when proper precautions are taken. But, if safety measures are ignored, welders face an array of hazards which can be potentially dangerous, including electric shock, fumes and gases, fire and explosions and more. Welding operators face an array of hazards, including electric shock, fumes and gases, fire and more. Employers should ensure all workers have an opportunity to comply with the following important guidelines in the workplace:
The philosophy that often guides the fabrication of welded assemblies and structures is "to assure weld quality.
The application determines what is good or bad. Generally, any weld is of good quality if it meets appearance requirements and will continue indefinitely to do the job for which it is intended. The first step in assuring weld quality is to determine the degree required by the application.
A standard should be established based on the service requirements. Standards designed to impart weld quality may differ from job to job, but the use of appropriate weld techniques can provide assurance that the applicable standards are being met.
Whatever the standard of quality, all welds should be inspected, even if the inspection involves nothing more than the welder looking after his own work after each weld pass. A good-looking weld surface appearance is many times considered indicative of high weld quality.
However, surface appearance alone does not assure good workmanship or internal quality. Nondestructive examination NDE methods of inspection make it possible to verify compliance to the standards on an ongoing basis by examining the surface and subsurface of the weld and surrounding base material.
Five basic methods are commonly used to examine finished welds: The growing use of computerization with some methods provides added image enhancement, and allows real-time or near real-time viewing, comparative inspections and archival capabilities.
A review of each method will help in deciding which process or combination of processes to use for a specific job and in performing the examination most effectively. Visual Inspection VT Visual inspection is often the most cost-effective method, but it must take place prior to, during and after welding.
Many standards require its use before other methods, because there is no point in submitting an obviously bad weld to sophisticated inspection techniques. Aside from good eyesight and sufficient light, all it takes is a pocket rule, a weld size gauge, a magnifying glass, and possibly a straight edge and square for checking straightness, alignment and perpendicularity.
Before the first welding arc is struck, materials should be examined to see if they meet specifications for quality, type, size, cleanliness and freedom from defects. Grease, paint, oil, oxide film or heavy scale should be removed.
The pieces to be joined should be checked for flatness, straightness and dimensional accuracy. Likewise, alignment, fit-up and joint preparation should be examined. Finally, process and procedure variables should be verified, including electrode size and type, equipment settings and provisions for preheat or postheat.
All of these precautions apply regardless of the inspection method being used. During fabrication, visual examination of a weld bead and the end crater may reveal problems such as cracks, inadequate penetration, and gas or slag inclusions. Among the weld defects that can be recognized visually are cracking, surface slag inclusions, surface porosity and undercut.
On simple welds, inspecting at the beginning of each operation and periodically as work progresses may be adequate.
Where more than one layer of metal filler is being deposited, however, it may be desirable to inspect each layer before depositing the next. The root pass of a multipass is most critical to weld soundness. It is especially susceptible to cracking, and because it solidifies quickly, it may trap gas and slag.
On subsequent passes, conditions caused by the shape of the weld bead or changes in the joint configuration can cause further cracking, as well as undercut and slag trapping. Repair costs can be minimized if visual inspection detects these flaws before welding progresses.Clean, grind, and deburr cut parts, and accomplish different finishes using various metal shop tools, including the angle grinder and its many attachments.
Learn how to change belts on the belt sander to suit the needs of every project. The most widely used types of welding are stick or arc, gas metal arc, gas tungsten arc, plasma arc, shielded-metal arc, submerged arc, electroslag, flux-cored, metal inert gas and tungsten inert gas.
The type of welding used usually depends on the thickness and form of the material. Welding is the. Any discussion on weld types and positions starts with the idea that it is important to distinguish between the joint and the weld.
Each must be described to completely describe the weld joint. There are many different types of welds, which are best described by their shape when shown in cross section. Mig welding can be used to weld steel, stainless steel and aluminum, all requires slightly different gasses welding wires, and amperage settings.
and due to the work requirements the heavier the metal being welded the more powerful welding machine needs to be. There are many different types of welds, which are best described by their shape when shown in cross section.
The most popular weld is the fillet weld, named after its cross-sectional shape. Fillet welds are shown by figure Nondestructive Testing in Welding. Request More Information. It’s easy – just fill out the form below and get ready for your exciting journey into a new career!
Welding Techniques for Different Types of Metals; Welding Training for Georgia Residents; Welders may use liquids, gases or even soap bubbles to accomplish this, which will.