Educating Welders about Quality Welds
During my life, I welded, supervised welders, engineered welds and inspected welds in many industries. Some welds were acceptable and some welds were rejected. It is important to note these terms, “accept and reject”. Every person (company and personal) involved in the welding operation needs to perform their assigned duties (design, materials, processes, and compliance). When there is a weakness in any one of these functions, the “welder” gets blamed for a bad weld.“Beauty is in the eye of the beholder”. This is also true for welds.
Welders are under tremendous pressure to produce. Good welders learn to become “inspectors” of their own work. The official QC welding inspector is not the first inspector or the only line of defense against weld defects. Every welder must be accountable and take responsibility for quality welding.
In business, welding is performed solely for economic purposes and hopefully financial gain by the company. The welder is merely one member of the team involved in the overall production of a product. The Quality Control (QC) inspector shouldn’t be the only one worried about weld quality. Most welders are such “can-do” individuals, that it is easy for managers to forget that there are other contributors to successful welding operations.
Sometimes, it is the poor performance or lack of performance by others that is the fundamental cause of weld rejects.
Every product designer must be trained to recognize a “quality weld”. Every welder must be trained to recognize the “quality weld” that the designer expects. The company welder is charged to perform work as instructed by his direct supervisor. Welders should do what they are told to do. The welder is one of the lowest persons in the organizational chart hierarchy. In reality, the welder should be at the top of the organization chart and all the other company employees should be supporting the welder.
Management must provide the welder with accurate drawings, a copy of the current welding code, customer approved specifications, and the training required to understand instructions about the type of weld that is expected.
Clear instructions to the welder include the commitment the company made to the customer. The welder is expected to comply with the designer’s intent and the customer’s expectation. These topics are essential for the welder to be able to make a quality weld and keep his job. The welder is truly the first line of defense against weld defects.
A common problem for many welders is timely deliver of adequate instructions to the shop floor about management’s expectations. Effective “Welding Management” is vital for continuous improvement of the welding process in every industry and every shop. Photograph 1. Welded Fabrication on Beam End shows a location where welding warpage and distortion must be minimal.
By definition, “a quality weld is a weld that meets the designer’s intent”. A problem in the production area is that a history of exceptionally perfect weld quality or acceptance of less than code quality welds sometimes interferes with the current welds and causes problems about what is required. It is important that every weld meets the code or drawing requirements and not exceed the weld size or fall short of the required quality. However, when the decision is made to always provide only minimum size welds that just meet the code, the weld may be rejected by other inspectors in subsequent manufacturing processes or when warranty issues arise.
Welder performance certification should be a requirement, before any welder begins work on production parts. From the first day of employment with the company, as a welder, every welder must demonstrate proficiency and the ability to weld as required for the specific assignment.
Properly managed and organized welding operations always utilize approved welding procedure specifications (WPSs) to communicate to all persons associated with the welding operations what is expected for a product. The WPSs contain procedural documentation concerning the design of the weld joint, the base material type and grade, the welding process, consumables & equipment, the essential variable ranges (volts, amperes, travel speed, etc.) the range and the weld quality expectations by the customer. All departments (designers, purchasing, operations, and quality) involved in welding need to have access to and understand the WPSs. They all must know what to expect in the final welds. The importance of this welding knowledge is essential for success.
Welders should consider the following when welding. In a production welding, always try to weld in the flat position. Designers know that fillet welds require the least joint preparation and clean-up. Avoid weld spatter, remove the slag and minimize time required for clean-up. Avoid grinding welds.
Avoid breathing the welding fumes and smoke. Photograph 2. Avoid Breathing the Fumes, depicts the welder with head and hood in the weld plume, breathing the fumes.
Management must take steps to emphasize the importance of welding. A few items that the welder should do are listed:
- Understand the latest revision of the print and welding symbols.
- Know the code, specification, essential variables and acceptance criteria.
- Know the correct time for welding inspections or “hold points” for QC inspection.
- Always keep the workplace safe, ventilated, well-lighted and suitably clean.
- Wear gloves, protective clothing, hood and lenses are in good repair.
- Wear clean, neat clothes and safety boots. Dress like a professional welder.
- Monitor the equipment condition and operation. Keep extra tips, cups, liners, etc.
- Wear prescription, safety glasses or magnifying, hood lenses when welding.
- Keep hand tools (pliers, screwdrivers, wire-cutters, etc.) readily available.
- Keep adequate consumables readily accessible and safely stored.
- Know common weld joint designs – clean and smooth weld surfaces, proper root openings, bevel grooves including the correct angles, backing or backgouging.
- Maintain parts at the work station and be supplied by assigned material handlers.
- Keep filler metal and consumables (gas, inserts, backing, etc.) readily available.
- Monitor the essential variables in the WPSs – amperes, volts, travel speed.
- Weld in the flat position or use a turntable, if possible.
- Know preheat and post weld heat treatment requirements and use a temp stick.
- Use the preferred technique – string or weave the weld for product consistency.
- Know the welding code requirements and scheduled nondestructive testing.
- Have a set of fillet weld gauges, a measuring tape, metal ruler and mechanical devices to measure for correct root openings and weld sizes.
- Realize that every time anything is done to a part, it costs the company money.
Welders can make use “in-plant” made visual samples as aids to remember the appearance of acceptable welds and rejected welds. Make a suitable wall mounted board to permanently keep these reminders available for easy reference to all welders, QC and managers. The welder must remember that “as the first inspector of every weld”, the accept-reject decision is made while the hood is “down” and the arc is “on”. Only the welder can actually see the puddle of the all-important root pass and catch a defect during the root weld pass or while the puddle is still molten.
It is important that the welder knows what is expected and is able to deliver good welds. Published acceptance criteria in the codes are a minimum standard of acceptability. The welder should avoid the minimum acceptable weld, because when a weld falls beneath that minimum, then rejects must be repaired. Photograph 3. Welders Must Know the Acceptance Criteria.
Visual inspection happens before, during and after welding. Talented welders, with a sense of pride in workmanship, add a level of confidence to the overall welding operation, meaning that at times that there could be less need for inspectors of final welds. Non-destructive testing tools for the welder make the sense for timely, in-process weld inspection. Aside from visual inspection criteria, welders can perform liquid penetrant inspection or magnetic particle tests of welds while in process and finished welds, before QC inspector’s checks. Welders who fail to perform personal inspections can drain a company’s finances.
Accountability and responsibility by all members of the weld team improves weld quality. Every person, designer, purchasing, operations, quality needs to leave their contact number with the welding supervisor to provide timely responses to welding difficulties on the shop floor immediately, day, night, or weekends. In-process welding is a real-time operation that waits for no one.
Welders should place their stencil # on every completed weld. When there are 6 welders on the payroll, when problems arise, you will realize that there are actually 7 welders in the shop. The 7th welder, who is responsible for the bad weld, is named “Nobody”. Photograph 4. Water Leak from the Outside to the Inside.
In general, welders have too much time to think when the arc is “on”. A welder must keep his mind on the welding and watch the puddle he is making. When the welder is thinking about personal problems, concentration is lacking and problems will arise. When a welder is anxious to get out the door at the end of the shift, it is easy to mentally quit thinking early about quality welding before “punching out“at the time clock, and rejects happen.
Welders and QC welding inspectors face a continual “push-pull” between the production of welded products. It is important to always remember that they are both on the same team and strive for efficiency, quality, and customer satisfaction. The sales department knows that customers demand that top quality welds be quickly delivered at a bare minimum price.
Individual welders must be ethical and always tell the truth. If new tools are needed, get them. If vision is a problem, get glasses or portable lights. If the weld is inaccessible, stop and change the design or create a sub-assembly. No one can inspect quality into a welded part. “Quality” is relative term and means compliance with the code and the designer’s intent.
Dr Grantham is a welding expert with more than 40 years experience welding, testing welders, metals and as an expert witness. Read more about Dr Grantham at www.jesseagrantham.com.