Quiz- Section 4: Specifications – CWI Part C – 7 Questions
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Section 4: Specifications
This subsection calls for good judgment, sound engineering, suitable operating practices, and attention to safety in the operation of welding equipment. Arc welding equipment shall be operated within the voltage and current ranges specified on the welding procedure specification. Gas welding equipment shall be operated with the fame characteristics and tip sizes given in the qualified WPS.
Paragraph 4.2.1 says that pipe and fittings must conform to API or any applicable ASME, ASTM, MSS, or ANSI specifications, but it then further states that materials that comply with the chemical and mechanical properties of any of these specifications are also acceptable, even if they are not manufactured in accordance with the specification. This suggests that the chemical and mechanical properties of any such material must be identified, preferably on the welding procedure specification, when used for an API 1104 application.
Paragraph 18.104.22.168 states that filler metals must conform to one of the listed AWS filler metal specifications. Other filler metals may be used as long as the applicable welding procedures are qualified.
Table 1, in Section 5 on pages 1 5-1 6, divides filler metals into nine groups, based on electrode characteristics and the welding processes that use them. It is important to note that the Group Numbers that API 1104 uses are different than the F-Numbers that AWS uses to group filler metals. For instance, the low-hydrogen SMAW electrodes are F-No. 4 electrodes as defined by AWS, but they are Group No. 3 electrodes in API 1104. Table 1 lists:
(a) Group Numbers for filler metals, electrodes, and fluxes.
(b) AWS Specifications.
(c) AWS Classifications for filler metals and electrodes.
(d) AWS Classifications for fluxes.
Group Nos. 1, 2, and 3 electrodes are for SMAW. Group No. 4 electrodes and fluxes are for SAW. Group No. 5 electrodes are for GMAW, GTAW, and PAW. Group No. 6 electrodes are for OFW and Group Nos. 7, 8, and 9 are for FCAW.
Be attentive to the footnotes in Table 1, which modify the requirements for use of certain electrodes, filler metals, or fluxes and may give additional rules.
Paragraph 22.214.171.124 requires protection of filler metals and fluxes from deterioration and excessive changes in moisture, although no definition of “excessive” is provided. Obviously, if the flux coating on a SMAW electrode is damaged, it should not be used because it will not operate properly. Low hydrogen SMAW electrodes (AWS classifications which end in 5, 6, or 8) must be stored in such a way that their coatings do not absorb excessive moisture from the atmosphere prior to use for welding.
Although it is not specifically required by API 1104, there are recommended good manufacturing practices for the storage and use of low-hydrogen SMAW electrodes in applicable AWS filler metal specifications. These include
(a) The storage of these electrodes in a heated, vented oven at a prescribed temperature after removal from their hermetically sealed containers,
(b) Limited exposure to the atmosphere, and
(c) Recommended minimum baking times and temperatures after atmospheric exposure.
Paragraph 126.96.36.199 addresses the various types of shielding gases used for welding. Inert shielding gases do not react chemically with the weld pool; they work by simply shielding the weld pool from interacting with the gases in the atmosphere. An active gas, however, does interact with either the arc, the weld pool, or in some cases, both. Inert gases include argon and helium. Active gases include carbon dioxide and oxygen. In GMAW, sometimes mixtures of inert and active shielding gases are used.
Gases must be relatively pure and dry and the shielding gas or gases to be used shall be qualified in accordance with the applicable essential variable rules for procedure qualification. API 1104 does not reference AWS A5.32 for purity requirements for shielding gases.
Paragraph 188.8.131.52 addresses storage and handling of gases for welding. Gases shall not be fled intermixed in their containers and gases of questionable purity or gases from damaged containers shall not be used.