SPW Product Catalogue 2019

FACTS & FIGURES
GAS PRESSURES - GAS WELDING AND CUTTING
Gas Welding:
Acetylene Pressure 100 kPa (15 psi)
Oxygen Pressure 100 kPa (15 psi)
Gas Cutting: (Manual)
Acetylene Pressure 100 kPa (15 psi)
Oxygen Pressure 200 kPa (30 psi)
Oxygen Cylinder:
Pressure when full 13700 kPa (Approx. 2000 psi)
Acetylene cylinder:
Pressure when full 1550 kPa (Approx. 200 psi)
Note: 15 psi = 100 kPa
GAS PRESSURES - GAS WELDING AND CUTTING
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Where preheating is required, the use of temperature-indicating crayons is strongly recommended as combining reasonable accuracy with convenience. Where
these are not available, however, an approximate idea of temperature may be obtained by the use of temper colours. These are colours produced on a clean
surface of the material due to extremely thin oxide films, and vary in colour with temperature. It should be noted that various alloying additions can have a
marked effect on oxidation, and the colours and temperatures indicated below apply only to plain carbon or low alloy steels. In order to obtain a reasonable
result the surface should be freshly ground, and care should be taken to avoid applying heat directly to the ground surface.
TEMPER COLOURS
Pale Straw
Straw
Dark Straw
Brownish Red
Violet
Dark Blue
Cornflour Blue
Pale Blue
Greyish Blue
200˚C
220˚C
230˚C
250˚C
280˚C
290˚C
300˚C
320˚C
340˚C
These colours are as seen by daylight and apply to plain carbon steels. They also apply only when the steel has been at temperature for a limited period,
prolonged periods producing a colour indicative of a higher temperature.
CHEMICAL NAMES AND FORMULA OF COMMON NAMES
TECHNICAL
COMMON NAME CHEMICAL NAME FORMULA DESCRIPTION
Muriatic Acid or, Spirits of Salts Hydrochloric Acid HCl Strongly fuming colourless liquid
Oil of Vitriol Sulphuric Acid H2SO4 Heavy, colourless, viscous liquid
Baking soda Sodium Bicarbonate NaHCO3 White powder
Black lead Carbon or Graphite C Black powder
Bleaching powder Calcium chloro-hypo chlorite CaOCI2 White powder smelling of chlorine
Bluestone (Blue Vitriol) Copper Sulphate CuSO45H2O Large blue crystals
Caustic Potash Potassium Hydroxide KOH White Deliquescent powder
Caustic Soda Sodium Hydroxide NaOH White Deliquescent powder
Chalk, Limestone, Marble Calcium Carbonate (more or less) CaCO3 White powder; Marble- crystalline form
Epsom Salts Magnesium Sulphate MgSO47H2O Small colourless crystals
Coke, Charcoal Carbon (impure) C Brittle black solid
Chile Saltpeter Sodium Nitrate NaNO3 White crystalline subst.
Condies Crystals Potassium Permanganate KMnO4 Small purple crystals
Glauber Salts Sodium Sulphate Na2SO41OH2O Large, colourless crystals
Green Vitriol Iron sulphate FeSO47H2O Green crystals
Laughing Gas Nitrous Oxide N2O Colourless gas
Lime (quicklime) Calcium Oxide CaO White powder
Limewater Solution of Calcium Hydroxide Ca(OH)2 Clear, bitter liquid
Liquid Ammonia Ammonium Hydroxide NH4OH Strongly fuming liquid
Litharge Lead Monoxide PbO Orange powder
Red lead Triplumbic Tetroxide Pb3O4 Fine, heavy red powder
Sal Ammoniac Ammonium Chloride NH4Cl White crystalline solid
Saltpeter (Nitre) Potassium Nitrate KNO3 Colourless crystals
Slaked Lime Calcium Hydroxide Ca(OH)2 White powder
Washing Soda Sodium Carbonate Na2CO31OH2O Large white crystals
Vinegar Acetic Acid (weak) CH3COOH Brown liquid
Copyright Produced with the permission of CIGWELD
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