Flashcards in Welder exam Deck (80)
CE = C + Mn /6 + (Cr + Mo + V) / 5 + (Ni +Cu) /15
Heat input equation (Q)?
What does the following stand for
Q = welding energy input
E = voltage
I = welding current amperage
V = welding speed
EI / V x 60/1000
What is ferrite stainless steel?
( High chromium low carbon, magnetic ).
Mild steel, carbon steel, stainless, cast, wrought iron
Aluminium, aluminium alloys, copper, brass gold, silver, tin, lead, zinc
Carbon phase diagram
Check answer use PowerPoint
Temperatures Grain structure etc
Refer to exam
and assignments ( perlite cementite etc)
What is a welding supervisors roll (AS 1796 / AS 2214)?
A welding supervisor is expected to control essential welding related aspects for any project, responsible for vessels, or structural production, over looking technical aspects (material welding procedures etc), safety and liaising with other parties included within the production.
Explain Duty cycle ?
The ratio of time during which the operator is actually welding to the total time he is on the job. Eg 30% duty cycle - welding at 150 for 3 minutes the welder will require 7 minutes rest.
Explains Deposition rate ?
The mass of metal deposited per minute, determined by the current used.
List two advantages and two disadvantages for a single vee and a double U joint
Name two main initiation mechanisms for gtaw.
HF and scratch start.
Describe electrode classification number E5518 from the AS / NZS 4855:2007 standard
Explain the term deposition efficiency in the relation to welding consumables ?
Explain brittle fracture?
This usually occurs with high strength or hardened steels. It is a quick fracture as the material have no room for ductility.
Explain fatigue ?
Fatigue is the form of structural failure caused by the action of fluctuation stresses.
This is also cause by containing weld defects -
* abrupt weld toes
* excessive reinforcement
* under cut
* lack of fusion, inclusions etc
Explain Stress corrosion ?
When cracking occurs through or across the grain boundaries.
Explain lamellar tearing ?
Not a weld defect. But is exposed from welding or fabrication. The defect appears below the weld on the HAZ boundaries. Lamellar tearing is a micro defect which is usually caused during the manufacture of plate.
Explain creep ?
When materials are subjected to high temperatures and load, the metal will tend to creep over time (deform), until it can not be used or even rupture.
Explain inter granular corrosion ?
This occurs in stainless steel and high nickel alloys. This is caused from rapid heating and forms around the HAZ area. Carbon migrates to the grain boundaries.
List and explain 7 types of destructive testing.
* Bend test - bending material in die to chec
What are some alloying elements ?
What does manganese do when added to steel ?
* Hardens steel when combine with carbon
* Helps produce fine grain structure
What does nickel do when added to steel ?
* Produces strength toughness resistance to abrasion.
* The steels do not suffer grain growth.
* Lowers the critical temperature.
* Minimizes distortion when quenched.
* Produces hardening properties.
* Can be magnetized.
What does chromium do when added to steel ?
* Raises the critical temperature of the steel.
* Above 11% becomes corrosion resistance.
* Creates stability
What does Molybdenum do when added to steel ?
* Increases tensile strength and toughness.
* Becomes brittle with heating.
* High resistance to creep.
What does silicon do when added to steel ?
* Helps with corrosion resistance.
What does copper do when added to steel ?
* About 1% is used in structural steels to promote hardness, fine grain, added strength and toughness.
* Adds magnetism.
What does Vanadium do when added to steel ?
* Increases tensile strength.
* Increases elastic limit.
* Increases resistance to fatigue.
* Used for high stressed.