Question | Answer |
Boiling Point | the temperature at which the metal changes from liquid state to vapor state |
thermal conductivity | a measure of the rate at which heat will flow through a material |
K-value | the amount of heat (in BTU's) transfered in one hour through 1sqft of a given material that is 1 inch thick and has a temperature difference between its surface of 1 degree farenheit--also called the coefficient of thermal conductivity |
R-value | represents the resistivity or resistance which is the reciprocal of conductivity or conductance. A good insulation material will have a high R-value. R=1/K |
specific heat | a measure of the quantity of heat required to increase the temperature of the material by a specific amount |
thermal expansion | the increase in the dimension of a metal caused by heat |
coefficient of linear thermal expansion | is a measure of the linear increase per unit length based on the change in temperature of the metal |
stress | the force or load being transmitted, divided by the cross sectional area transmitting the load--s=f/A |
strain | the internal reactive to stress or applied force |
yield point | the point at which there is appreciable elongation without a corresponding increase in load. we use yield point to determine yield strength |
ultimate strength | highest ordinant on a stress strain curve--tensile strength or highest strength |
full penetration | weld metal throughout the entire cross section of the weld joint |
partial penetration | has unfused areas |
allowable working stress | maximum stress level that is allowed anywhere within the weldment--allowable welding stress, allowable unit stress, and allowable weld stress |
strength | the ability to withstand the action of external forces without breaking |
ductility | a characteristic that allows a metal to be stretched or otherwise changed in shape without breaking and to retain the change shape after the load has been removed |
hardness | the resistance of a metal to local penetration by a harder substance |
impact strength | the resistance of a metal to impact and is determined by measure the energy absorbed in the fracture |
single stage regulator | indicates a pressure drop as the cylinder content is consumed--1000psi=10psi, 900psi=9psi |
2 stage regulator | maintains steady outlet pressures and flow rates during long periods of operation--1000psi=10psi, 900psi=10psi |
jump | a momentary pressure increase when the torch valves are closed |
creep | the working pressure side of the regulator increases to unusually high level after the torch valve is closed |
reverse flow check valves | allows the gas to flow in one direction only |
flash back arrestor | during a flashback, a filter stops the flame and activates a gas shut off valve--common occurence in cutting projects |
manufacturing processes | unfinished materials and converting into a finished product |