Fig. 2 — Welder breaking the fillet weld to assess the weld for internal defects such as incomplete fusion to the root, slag inclusions, piping porosity, etc. Inspection Trends / Spring 2011 31 If the client does not know what welding standard is applicable, I must help them determine what welding standard is appropriate. I begin by asking a few basic questions: 1. What are you welding (structural steel, pressure vessels, pressure piping, machinery, railroad equipment, shipboard equipment, etc.)? 2. Who are your customers? 3. Did the customer issue a purchase order? 4. Did the purchase order reference a welding standard, code, or specification? 5. Do you have a copy of the purchase order and welding standard? 6. Did the customer issue a drawing for the part or components being welded? Their response to the questions typically pushes us toward a recognized welding standard or one that was developed by the customer (a common practice in the aerospace and petrochemical industries). A little information mining usually results in finding a reference to a welding standard in the purchase order or project specifications. On rare occasions, I have recommended a recognized welding standard based on the type of product if one was not imposed by a customer. The next question is what base metal are you welding? They are usually welding a ferrous metal. Nonferrous metals only account for about 5% of the tonnage of metal modern industry uses; that means there is a 95% chance the client is welding a ferrous metal. A follow-up question: Are you welding grooves or fillets or some other type of weld? The usual response is “we weld mostly fillet welds.” This is reasonable because fillet welds account for the majority of the welds made in manufacturing or fabrication operations. Next question: “Do you weld any grooved joints?” The typical response is “Yes, but most of our welds are fillets.” My advice is “That’s fine, but if you make even a single groove weld, you have to use a test that utilizes a grooved weld preparation. In general, groove weld qualification qualifies the welder for both grooves and fillet welds, but a welder qualified by taking a fillet weld test is only qualified for fillet welds.” A common response to a question about welding positions is, “Well, most of the work is done in the flat position.” “So, the welder never has to weld in the vertical or overhead positions?” is my next query. That question causes the client to wince a little, but a meeting of the minds comes about and the test positions are agreed to. Another question is “Are you welding structural shapes, plate, or pipe?” Finally, as I near the end of the information-gathering process, I ask, “Do you have a WPS that describes how the weld is made?” That question is merely a courtesy, since I know full well the next words I am likely to hear are, “A what?” The Welding Procedure Specification (WPS) Contrary to the belief held by some people, welders are not psychic nor can they read minds. Tossing a couple of test coupons on the welding bench with a simple command of “weld these” isn’t sufficient information for the welder to understand what is expected. The welder needs specific instructions on how the test coupons are to be assembled and welded. Does the welder have to weld the test coupons in accordance with a particular welding procedure specification? I say yes if for no other reason than I do not want any surprises when the welder settles in to take the welding performance test. And, yes, I do write a specific WPS for the welder qualification test. The WPS tells the welder the welding process, base metal, filler metal, filler metal diameters, joint details including the root opening, and whether backing is required. I do not simply hand the welder a generic WPS that states it is applicable to all grooves and all fillets. The specific WPS used for welder qualification depicts the joint and the joint details the welder is to use, and lists the welding process and ranges for various welding parameters. It isn’t enough to hand the WPS to the welder. I review the WPS with the welder item by item so there are no questions of how the test coupons are to be welded. Test Rules I have already said I do not like surprises while taking or administering a welder qualification test. I remember an inspector telling one of my friends, “You can’t weave on this test” as he rejected my friend’s test piece. Fortunately, I had not started welding yet. I have developed a set of test rules to ensure that surprises do not happen when I am giving a qualification test. I hand a printed copy of the test rules to the welder, then review them and answer any questions he or she may have. What do I include in the test rules? The first thing listed is the required personal protective equipment the — continued from page 28
Inspection Trends - April 2011 - Spring
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