Welding Codes and Standards Ch 22 PDF

# Chapter 22: Welding Codes and Standards ## Objectives After completing this chapter, the student should be able to: - Explain the difference between qualification and certification. - List the major considerations for selecting a code or standard. - Write a welding procedure and specification....

# Chapter 22: Welding Codes and Standards ## Objectives After completing this chapter, the student should be able to: - Explain the difference between qualification and certification. - List the major considerations for selecting a code or standard. - Write a welding procedure and specification. - Identify the three most common codes and describe their major uses. - Outline the steps required to certify a weld and welder. - Explain how a tentative WPS becomes a certified WPS. ## Key Terms | Term | Description | |---|---| | API Standard 1104 | | | ASME Section IX | | | AWS D1.1 | | | code | | | Procedure Qualification Record (PQR) | | | specification | | | standard | | | Welding Procedure Specification (WPS) | | | Welding Schedule| | ## Introduction It is important to know that any weld produced is going to be the best one for the job. A method is also needed to ensure that each weld made in the same plant or on the same type of equipment in another plant will be of the same quality. To meet these requirements various agencies have established codes and standards. These detailed written outlines explaining exactly how a weld is to be laid out, performed, and tested have made consistent quality welds possible. By having the required information, skilled welders in shops all around the city, state, country, or world can make the same weld to the same level of safety, strength, and reliability. A testing procedure to certify the welder ensures that the welder has the skills to make the weld. Passing a weld test is much easier when all of the detailed information is provided. Selecting the code or standard to be used to judge a weld is equally as important as having a skilled welder. Not every product welded needs to be manufactured to the same level. The decision on the appropriate code or standard can be one of the most important aspects of welding fabrication. If the wrong one is selected, the cost of fabrication can be too high, or the parts might not stand up to the service. ## Codes, Standards, Procedures, and Specifications A number of organizations publish codes or specifications that cover a wide variety of welding conditions and applications. The selection of the specific code to be used is made by the engineers, designers, or governmental requirements. Codes and specifications are intended to be guidelines only and must be qualified for specific applications by testing. A welding code or standard is a detailed listing of the rules or principles that are to be applied to a specific classification or type of product. A welding specification is a detailed statement of the legal requirements for a specific classification or type of weld to be made on a specific product. Products manufactured to code or specification requirements commonly must be inspected and tested to ensure compliance. A number of agencies and organizations publish welding codes and specifications. The selection of the particular code or specification to a weldment can be the result of one or more of the following requirements: - **Local, state, or federal government regulations** - Many governing agencies require that a specific code or standard be followed. - **Bonding or insuring company** - The weld must be shown to be fit for service requirements as established through testing. A bonding or insuring company must feel that the product is the safest that can be produced. - **End user (customer) requirements** - The manufacturer considers cost and reliability; that is, as stricter standards are applied to the welding, the cost of the weldments increases. The more lax the standard, the lower the cost, but the reliability and possibly the safety also decrease. - **Standard industrial practices** - The code or standard used is considered to be the standard one for the industry and has been in use for some time. Following are the three most commonly used codes: - **API Standard 1104**, American Petroleum Institute - Used for pipelines - **ASME Section IX**, American Society of Mechanical Engineers - Used for pressure vessels and nuclear components - **AWS D1.1**, American Welding Society - Used for bridges, buildings, and other structural steel The following organizations publish welding codes and/or specifications. Most can be contacted for additional information and current price list either directly or through the World Wide Web. - AAR - AASHTO - AIA - AISC - ANSI - API - AREMA - ASME - AWS - AWWA - MIL - SAE ## Welding Procedure Qualification ### Welding Procedure Specification (WPS) A welding procedure specification is a set of written instructions by which a sound weld is made. Normally, the procedure is written in compliance with a specific code, specification, or definition. **Welding Procedure Specification (WPS)** is the standard terminology used by the _American Welding Society (AWS)_ and the _American Society of Mechanical Engineers (ASME)_. **Welding Schedule** is the standard federal government, military, or aerospace terminology denoting a WPS. The shortened term _welding procedures_ is the most common term used by the industry to denote a WPS. The WPS lists all of the parameters required to produce a sound weld to the specific code, specifications, or definition. Specific parameters such as welding process, technique, electrode or filler, current, amperage, voltage, preheat, and postheat should also be included. The procedure should list a range or set of limitations on each, such as amps = 110-150, voltage = 17-22, and so on, with the more essential or critical parameters more closely defined or limited. The WPS should give enough detail and specific information so that any qualified welder could follow it and produce the desired weld. The WPS should always be prepared as a tentative document until it is tested and qualified. ### Qualifying the Welding Procedure Specification The WPS must be qualified to prove or verify that the list of variables - amperage, voltage, filler, and so on - will provide a sound weld. Sample welds are prepared using the procedure and specifications listed in the tentative WPS. A record of all the parameters used to produce the test welds must be kept. Be sure to record the specifics for the parameters such as voltage, amperage, and so on. This information should be recorded on a form called the **Procedure Qualification Record (PQR)**. In most cases, the inspection agency, inspector, client, or customer will request a copy of both the WPS and the PQR before allowing production welding to begin. ### Qualifying and Certifying The process of qualifying and then certifying both the WPS and welders requires a number of specific requirements. The requirements may vary from one code or standard to another, but the general process is the same for most. Before you invest in the testing required to qualify and certify processes and welders under a code, you must first obtain a copy of the code you are planning to use. The requirements of codes and standards change from time to time, and it is important that your copy is the most recent version. The following is a generic schedule of required activities you might follow when qualifying and certifying the welding process, the welder(s), and/or welding operator. 1. A tentative welding procedure is prepared by a person knowledgeable of the process and technique to be used and the code or specification to be satisfied. 2. Test samples are welded in accordance with the tentative WPS, and the welding parameters are recorded on the PQR. The test must be witnessed by an authorized person from an independent testing lab, the customer, an insurance company, or other individual(s) as specified by the code or listing agency. 3. The test samples are tested under the supervision of the same individuals or group that witnessed the test by the applicable requirements, codes, or specifications. 4. If the test samples pass the applicable test, the procedure has completed qualification. It is then documented as qualified/finalized and is released for use in production. 5. If the test samples do not pass the applicable test, the tentative WPS value parameters are changed as deemed feasible. Test samples are then rewelded and retested to determine if they do or do not meet applicable requirements. This process is repeated until the test samples pass applicable requirements, and the procedure is finalized and released. 6. The welder making the test samples to be used in qualifying the procedure is normally considered qualified and is then certified in the specific procedure. 7. Other welders to be qualified weld test samples per the WPS, and the samples are tested per applicable requirements. If the samples pass, the welder is qualified to the specific procedure and certified accordingly. 8. A qualified WPS is usable for an indefinite length of time, usually until a process considered more efficient for a particular production weld is found. 9. The welder's qualification is normally considered effective for an indefinite period of time, unless the welder is not engaged in the specific process of welding for which he or she is qualified for a period exceeding six months; then the welder must requalify. Also a welder will need to requalify if for some reason the qualification is questioned. Figure 22-1 and Figure 22-2 are two examples of test records used to qualify a WPS and a welder for plate, PQR. ## General Information Normally, the format of the WPS is not dictated by the code or specification. Any format is acceptable as long as it lists the parameters or variables (essential or nonessential, amps, volts, filler identification, etc.) listed by the code or specification. Most codes or specifications appear in an acceptable or recommended format. Ideally, the WPS should include all of the information required to make the weld. A welder should be able to be given the WPS without additional instructions and produce the weld. To help with this, it is often a good idea to include supplementary information with each WPS. The information might be basic instructions for the process. With some WPSs you might include several pages as attachments that can give the welder a little review of the setup, operation, testing, inspecting, and so on, which will help to ensure accuracy and uniformity in the welds. Essential variables are those parameters in which a change is considered to affect the mechanical properties of the weldment to the point of requiring requalification of the procedure. Nonessential variables are those parameters in which a change may be made without requiring requalification of the procedure. However, a change in nonessential variables usually requires a revision to be made. There are large differences among various codes. The AWS D1.1, _Structural Welding Code Steel_, allows some prequalified weld joints for specific processes (SMAW, SAW, FCAW, and GMAW). A written procedure is required for these joints, but since the procedure is tentative, it does not require support via a written PQR, Figure 22-3. The Procedure Qualification Requirements regarding positions for groove welds in plate differ among codes. Some codes may require a written procedure for each position. The ASME Section IX, however, qualifies a welder for the 1G position when the welder qualifies for 2G, 3G, or 4G. Ordinarily, the welder must be qualified/certified in accordance with a specific WPS. The welder's qualifying test plate may be examined radiographically or ultrasonically in place of bend tests. Specific codes or specifications must be referenced for details of the number of actual tensile, bend, or other type of test specimens and tests to be performed. For example, AWS D1.1 and ASME Section IX do not require a "Nick-Break Test Specimen," but API Standard 1104 does require it. ## Practice 22-1 ### Writing a Welding Procedure Specification (WPS) Using the form provided and following the example, Figure 22-3, you will write a welding procedure specification. Figure 22-4 is a form that is a composite of sample WPS forms provided by AWS, ASME, and API codes. You may want to obtain a copy of one of the codes or standards and compare a weld you made to the standard. Most of the unique information is provided in this short outline. Additional information that may be required for this form can be found in figures in this chapter. You may need to refer to some of the chapters on welding or to your notes to establish the actual limits of the welding variables (voltage, amperage, gas flow rates, nozzle size, etc.). **NOTE**: Not all of the blanks will be filled in on the forms. The forms are designed to be used with a large variety of weld procedures, so they have spaces that will not be used each time. 1. The WPS number is usually made up following a system established by the company. This number may or may not include coded information relating to the date it was written, who wrote it, material or process data, and so on. 2. Date that the WPS was written or effective. 3. The welding process(es) that will be used to perform the weld, such as SMAW, GMAW, GTAW, and so on. 4. The actual material type and thickness or pipe type and diameter and/or wall thickness. If all the material or pipe being joined is the same, then the same information will appear before and after "to." 5. Fillet or groove weld and the joint type, such as butt, lap, tee, and so on. 6. Thickness range qualified or diameter range qualified: For both plate and pipe, a weld performed successfully on one thickness qualifies a welder to weld on material within that range. See Table 22-1 for a list of thickness ranges. 7. Material position: 1G, 2G, 3G, 4G, IF, 2F, 3F, 4F, 5G, 6G, 6GR, Figure 22-3 8. Base metal specification: This is the ASTM specification for the type and grade of material, including the P-number, Table 22-2. 9. If a backing material is used, then its ASTM or other specification information must be included here. 10. Classification number: This is the standard number found on the electrode or electrode box, such as E6010, E7018, E316-15, ER70S-3, or E70T-1. 11. Filler metal specification number: The AWS has specifications for chemical composition and physical properties for electrodes. Some of these specifications are listed in Table 22-3. 12. F-number: A specific grouping number for several classifications of electrodes having similar composition and welding characteristics. Table 22-4 lists the F-number corresponding to the electrode used. ## Practice 22-2 ### Procedure Qualification Record (PQR) Following the procedure you wrote in Practice 22-1, you are going to make the weld to see if your tentative welding procedure and specification can be certified. Complete a copy of the form provided to record all of the appropriate information, Figure 22-2. Complete a copy of the "Student Welding Report" listed in Appendix I or provided by your instructor. 1. The PQR number is usually made up following a system established by the company. This number may or may not include coded information relating to the product being welded, material or process data, and the like. 2. The WPS number on which the PQR is based. 3. The date on which the welding took place. 4. Base metal specification: This is the ASTM specification for the type and grade of material. 5. Table 22-2 lists some commonly used metals and their P-numbers. 6. Test material thickness (or) test pipe outside diameter (OD) (and) wall thickness. 7. Manual welding processes are used to qualify a welder. Specify the process, such as GMAW, FCAW, SMAW, GTAW, and so on. 8. Automatic welding processes are used to qualify a welding operator. Specify the process (SAW, ESW, etc.). | Type of Material | |---|---| | P-1 | Carbon steel | | P-3 | Low alloy steel | | P-4 | Low alloy steel | | P-5 | Alloy steel | | P-6 | High alloy steel-predominantly martensitic | | P-7 | High alloy steel-predominantly ferritic | | P-8 | High alloy steel-austenitic | | P-9 | Nickel alloy steel | | P-10 | Specialty high alloy steels | | P-21 | Aluminum and aluminum-base alloys | | P-31 | Copper and copper alloy | | P-41 | Nickel | | Specification Numbers | |---|---| | A5.10 | Aluminum-bare electrodes and rods | | A5.3 | Aluminum-covered electrodes | | A5.8 | Brazing filler metal | | A5.1 | Steel, carbon, covered electrodes | | A5.20 | Steel, carbon, flux cored electrodes | | A5.17 | Steel-carbon, submerged arc wires and fluxes | | A5.18 | Steel-carbon, gas metal arc electrodes | | A5.2 | Steel-oxyfuel gas welding | | A5.5 | Steel-low alloy covered electrodes | | A5.23 | Steel-low alloy electrodes and fluxes-submerged arc | | A5.28 | Steel-low alloy filler metals for gas shielded arc welding | | A5.29 | Steel-low alloy, flux cored electrodes | | Group Designation | Metal Types | AWS Electrode Classification | |---|---|---| | F1 | Carbon steel | EXX20, EXX24, EXX27, EXX28 | | F2 | Carbon steel | EXX12, EXX13, EXX14 | | F3 | Carbon steel | EXX10, EXX11 | | F4 | Carbon steel | EXX15, EXX16, EXX18 | | F5 | Stainless steel | EXXX15, EXXX16 | | F6 | Stainless steel | ERXXX | | F22 | Aluminum | ERXXXX | | A No. | Types of Weld Deposit | C% | Mn % | Si % | Mo % | Cr % | Ni % | |---|---|---|---|---|---|---|---| | 1 | Mild steel | 0.15 | 1.6 | 1.0 | - | - | - | | 2 | Carbon-moly | 0.15 | 1.6 | 1.0 | 0.4-0.65 | 0.5 | - | | 3 | Chrome (0.4 to 2%)-moly | 0.15 | 1.6 | 1.0 | 0.4-0.65 | 0.4-2.0 | - | | 4 | Chrome (2 to 6%)-moly | 0.15 | 1.6 | 2.0 | 0.4-1.5 | 2.0-6.0 | - | | 5 | Chrome (6 to 10.5%)-moly | 0.15 | 1.2 | 2.0 | 0.4-1.5 | 6.0-10.5 | - | | 6 | Chrome-martensitic | 0.15 | 2.0 | 1.0 | 0.7 | 11.0-15.0 | - | | 7 | Chrome-ferritic | 0.15 | 1.0 | 3.0 | 1.0 | 11.0-30.0 | - | | 8 | Chromium-nickel | 0.15 | 2.5 | 1.0 | 4.0 | 14.5-30.0 | 7.5-15.0 | | 9 | Chromium-nickel | 0.30 | 2.5 | 1.0 | 4.0 | 25.0-30.0 | 15.0-37.0 | | 10 | Nickel to 4% | 0.15 | 1.7 | 1.0 | 0.55 | 0.8-4.0 | - | | 11 | Manganese-moly | 0.17 | 1.25-2.25 | 1.0 | 0.25-0.75 | 0.85 | - | | 12 | Nickel-chrome-moly | 0.15 | 0.75-2.25 | 1.0 | 0.25-0.8 | 1.5 | 1.25-2.25 |