CWB Level 2 All Modules Exam - Complete Solutions (Answered)

CWB Level 2 All Modules Exam - Complete Solutions (Answered) What is the main alloying element in the AISI 200 series? (A) chromium (B) chromium and nickel (C) manganese What is the main alloying element in the AISI 300 series? (A) chromium (B) chromium and nickel (C) manganese Note: Steels in this series are austenitic! What is the main alloying element in the AISI 400 series? (A) chromium (B) chromium and nickel (C) manganese Note: Steels in this series are ferritic or martensitic! When referring to the 300 series, what does the popular term "18-8 stainless" mean? 18% Chromium, 8% Nickel The hardness of martensitic stainless steels is determined largely by the __________ content. Carbon Note: The hardness of martensitic stainless can also be adjusted by the following methods: 1) Adjusting austenitizing temperature 2) Tempering after cooling 3) Heating to above 950° C and quenching What are the (x5) main categories of stainless steel? Hint: The first one is "Austenitic". 1) Austenitic 2) Martensitic 3) Ferritic 4) Duplex 5) Precipitation Hardening Martensitic and ferritic stainless steels are: (A) Magnetic (B) Non-magnetic Austenitic stainless steels are: (A) Magnetic (B) Non-magnetic Which crystalline structure does regular low-carbon steel have at room temperature? (A) FCC (B) BCC At what temperature does regular low-carbon steel change from BCC to FCC structure? Hint: It's "transformational temperature". 723° C What is the transformational temperature of pure iron? Hint: When it changes from BCC to FCC 912° C Given identical welding parameters, which of the following will result in a 50% larger weld fusion zone? (A) Carbon steel (B) Stainless steel Note: Less heat is required in stainless steel to produce the same size weld due to its thermal properties Stainless steel welding is __________ to oxygen than carbon steel welding. (A) Less tolerant (B) More tolerant Note: Too much oxygen or Co2 present during welding will over-oxidize the chromium -- loss of alloying elements and undesirable properties in the completed weld (hence why inert shielding gas is used) Which type of stainless steel does not suffer from hydrogen embrittlement or hydrogen-induced cracking? Hint: it's FCC structure is the reason for this (A) Austenitic (B) Martensitic (C) Ferritic Solidification cracking in stainless (longitudinal crack in the last part of the weld bead) can be caused by the presence of impurities such as __________ and phosphorus. Sulphur True or False: The Schaeffler Diagram was produced to group alloying elements as "Austenite stabilizers" and "Ferrite stabilizers". True Austenite stabilizers are nickel equivalents that promote austenite Ferrite stabilizers are chromium equivalents that promote ferrite The DeLong diagram was created because the Schaeffler Diagram did not account for the very important effect of __________ on stainless steels. (A) Oxygen (B) Carbon (C) Nitrogen (D) Argon What polarity is typically used for plasma arc cutting? DCEN Cellulosic SMAW rods contain a moisture content of: (A) 1-3% (B) 3-7% (C) 7-10% (D)10-30% What temperature are low-hydrogen SMAW electrodes stored at? 120° C (250° F) How many times can a low-hydrogen SMAW electrode be re-baked? Once What kind of wire-feeder is required when opting to use CC on a wire-feed welding process? (A) Constant speed (B) Variable speed Select the correct definitions for "cast" and "helix" when it comes to welding wire. - How much unrestrained wire coils up off a flat surface - The unrestrained diameter of coil "Helix" - How much unrestrained wire coils up off a flat surface "Cast" - The unrestrained diameter of coil Which of the following classes of FCAW wire has similar ingredients to 7018 SMAW rod? (A) Basic (B) Rutile Which polarity is typically used for SAW? DCEP After the hyphen in a FCAW wire designation, the digit containing either an L, M, or H refers to which alloying element? Manganese Hardness __________ with cooling rate. (A) Increases (B) Decreases "Hot shortness" is usually a result of high __________ content in steel. Sulphur When using an X-ray machine, increasing the voltage produces a __________ wavelength. (A) Longer (B) Shorter Which of the following produces a shorter wavelength? (A) Cobalt-60 (B) Iridium-192