1. MODULE –7
Metric Practice for Welding Inspection.
SI Le Systeme Internationale D’ Unites
133/184—ANSI/ AWS 1.1:1998- Metric practice guide for the welding industry. As per
act signed in 1988 by president Reagan , each federal agency must use metric system by
1992.
Base for length measurement is Meters and weight in Kilograms, Liquid volume in
Liters. Pressure stress Pa Pascal 1 PSI= 6895 Pascal.
Energy – Joule J.
Electric Current Ampere-- A.
Frequency Hertz -- Hz.
Mega –M- 106.
Kilo= K 103.
Deci d= 0.1—10-1 .
Centi c 0.01 – 10-2 .
Milli –m 0.001- 10-3 .
135/184 -- Current density A/ mm2,
Deposition rate Kg/Hr,
Force- Newton N.
Flow rate L/Minute.
Fracture toughness Mega Newtons Meter -3/2 – MN.m-3/2
Power density Watts/M2,
Pressure (Gas and Liquid )
Killo Pascal KPa= 1000N/M2,
Pressure Vacuum Pascal Pa= N/M2, Tensile Strength- Mega Pascal MPa= 106 N/M2 ,
Wire feed speed—millimeter/ Sec= mm/sec.
SCIENTIFIC NOTATION—SN In SN the decimal is always moved to the immediate
right of the first digit other than zero. The final answer should be configured in to
scientific notation i.e. only one digit greater than one to left of the decimal point by
adjusting the exponent.
Rounding off—Rule 1 – Increase the last retained digit by one if the next digit to its right
is 5 or greater/larger.
Rule 2- Retain the last digit unchanged if the next digit to its right is less than 5.
S I unit symbols are not capitalized except for those derived from a proper name.
A – ampere, K- Kelvin, N- Newton, J- joule, m-meter, kg kilogram.
Following 5 prefixes symbols are capitalized. E- exa, P peta, T- tera, G giga, M mega.
Commas are not used while writing digital nos. Unit, symbols and names are never used
together, meter per second is correct but meter/s is not correct.
END