Weld 301C 2025 Exam | Questions and Answers

Weld 301C 2025 Exam | Questions and Answers What is the maximum carbon content of a low carbon nickel alloy? 0.02% Which series of stainless steel can be either ferritic or martensitic? 400 series What is the significance of an SMAW stainless steel electrode with the suffix 15? It has a lime coating and can only be used on DCRP Which AISI Series of stainless steel is a "chrome steel"? 500 series Which nickel alloy is the most corrosion resistant? Hastelloy Why is GTAW usually used for precipitation hardenable nickel alloys instead of SMAW? The Aluminum and titanium do not transfer well across the SMAW arc What is the % range that cladding is of the total material thickness? 5% - 50% How do you harden austenitic stainless steels? Cold working What are the different ways to prevent carbide precipitation? Limit Carbon, Add Stabilizers, limit heat input, use a short arc, follow weld procedures Describe Austenite A microstructure that only occurs in steels at elevated temperatures above the upper critical but occurs in NIckel at all temperatures What is the most common type of Stainless Steel in the welding industry? Austenitic How can you quickly check to see if a stainless steel is austenitic? Use a magnet Which 2 types of stainless are called straight chrome and have a BCC microstructure? Ferritic and Martensitic What technique is recommended when performing a root pass in the downhill progression? Drag Technique What do you call a localized area of excessive penetration? fall through At what temperature is preheat required when welding nickel and nickel alloys? 0 degrees C (32 degrees F) What is the face to center measurement of a 6" long radius Ell? 9" What structural shape is designated MC? miscellaneous channel iron What external vessel attachment has to be on every pressure vessel? Name Plate What formula is used for calculating the face to center measurement of a LR Ell? NPS x 1.5 How is W shape identified? Distance from flange face to flange face x weight (lb/ft or kg/M) Up to what size are xh pipe and sch 80 the same? 8" What type of orthagraphic pipe drawing should be used when more clarity is needed? double line What internal vessel attachment is used to ensure that a minimum liquid level is maintained? Weir A horizontal pressure vessel is adentified by which measurements? OD x length Why are piping bridles used on pressure vessels? To show liquid levels What does an "X" or a dot indicate on a piping drawing? A weld Why are valve trays more common than bubble cap trays on a vertical vessel? their simplicity, low cost and minimal maintenance What is the purpose of a tray on a vertical vessel? To hold liquids but allow gases to pass through the liquids What shape of vessel head is considered to be the strongest? Hemispherical What is the purpose of a bootleg on a pressure vessel? to allow a heavier liquid to separate from a lighter liquid Which bonding process accounts for 90% of the clad material produced world wide? Co-rolling What is the maximum allowable undercut of a 4GF as per CSA 47.1? 1/32" (.8mm) What do you call the distance between holes, across the angle iron clips on the end of a beam? Spread What do you call the center to center distance between holes along the same center line? Pitch What does GOSL stand for? Gauge outstanding leg Which category of weld on a vessel is a circumferential weld that joins shells together or shells to the vessel heads? category B Which category of weld on a vessel is a longitudinal seam or a circumferential seam joining a hemispherical head that was fabricated in an orange peel fashion? category A Which category of weld on a vessel is a nozzle to shell weld? category D Which category of weld on a vessel is a flange to pipe weld on a nozzle? category C Nominal pipe size indicates the inside diameter of a standard wall pipe up to what size? 12" (14" the pipe size becomes equal to the OD Std wall and sch40 are the same thing up to what pipe size? 10" What is the difference between eccentric and concentric reducers? concentric share a common center line and eccentric is flat on top or bottom What is the turn radius or face to center formula for a short radius 90 degree Ell? = NPS How many types of heads are there for pressure vessels? 3, ellipsoidal, spherically dished (torispherical), and hemispherical What scale are isometric drawings drawn to? They are not drawn to scale The process of cutting the flange om an S shape or W shape to narrow it's width is known as what? Blocking From what perspective is a site plan drawn? Directly above aka plan view Austenitic stainless steels always keep what microstructure? Face Centered Cubic (FCC) What does the addition of molybdenum do to stainless steels? Improves high temperature strength and resistance to pitting corrosion What action is performed when breaking the arc using GTAW in a groove weld? tailing out What is the color code and current type for a 2% thoria electrode? red, DCEN What is the purpose of a baffle in a vessel? to change the direction of the fluid or gas What type of stainless steel is commonly used for the fabrication of automotive exhaust systems? Ferritic Which grade of stainless steel is most affected by overheating? Austenitic due to it's ability to get carbide precipitation How many tacks are used on the B-pressure test and what is the correct size? 4 tacks, 1/2" - 3/4" How many face and root bends are there on a B-Pressure test? 4 face bends and 4 root bends When using GMAW to weld nickel and nickel alloys, what transfer modes are commonly used? Spray or pulsed spray transfer When was stainless steel discovered? Early 1900's At what temperature does carbide precipitation occur? 800 - 1500 degrees F What is one reason that mild steel does not require a back purge when placing a root pass with GTAW? the filler rod has deoxidizers in it What effect does a keyhole have on the dip technique when welding with GTAW? It is detrimental leading to fall through Which element is mainly responsible for forming the protective oxide layer on stainless steel? Chromium What is a concern when welding ferritic stainless steel? Grain growth What is the recommended land for a 3G using GTAW? 0 - 1/16" When working with nickel, how far back from the joint should foreign materials be cleaned? 2" (51mm) Which series of stainless steel contain an appreciable amount of nickel? 200 and 300 What is the maximum material thickness that can be welded using GTAW from both sides with no joint preparation? 3/8" At what material thickness is cladding considered? cladding should be considered when material is over 3/8" What is the maximum carbon content in an ELC stainless steel? 0.03% What is the recommended torch inclination for the root and wash pass using GTAW on a 3G?