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When the carbon equivalent is between 0.40 and 0.60 weld preheat may be necessary. When the carbon equivalent is above 0.60, preheat is necessary, postheat may be necessary. The following carbon equivalent formula is used to determine if a spot weld will fail in high-strength low-alloy steel due to excessive hardenability: [2]
The weldability, also known as joinability, [1] of a material refers to its ability to be welded. Many metals and thermoplastics can be welded, but some are easier to weld than others (see Rheological weldability). A material's weldability is used to determine the welding process and to compare the final weld quality to other materials.
The relative importance of the various alloying elements is calculated by finding the equivalent carbon content of the material. The fluid used for quenching the material influences the cooling rate due to varying thermal conductivities and specific heats. Substances like brine and water cool the steel much more quickly than oil or air. If the ...
Welding - Guidance on the measurement of preheating temperature, interpass temperature and preheat maintenance temperature ISO 13918: Welding - Studs and ceramic ferrules for arc stud welding: ISO 13919-1: Welding - Electron and laser-beam welded joints - Guidance on quality level for imperfections - Part 1: Steel ISO 13919-2
An aqueous solution containing 120 mg NaHCO 3 (baking soda) per litre of water will contain 1.4285 mmol/l of bicarbonate, since the molar mass of baking soda is 84.007 g/mol. This is equivalent in carbonate hardness to a solution containing 0.71423 mmol/L of (calcium) carbonate, or 71.485 mg/L of calcium carbonate (molar mass 100.09 g/mol).
The Hazen–Williams equation is an empirical relationship that relates the flow of water in a pipe with the physical properties of the pipe and the pressure drop caused by friction. It is used in the design of water pipe systems [ 1 ] such as fire sprinkler systems , [ 2 ] water supply networks , and irrigation systems.
A Assuming an altitude of 194 metres above mean sea level (the worldwide median altitude of human habitation), an indoor temperature of 23 °C, a dewpoint of 9 °C (40.85% relative humidity), and 760 mmHg sea level–corrected barometric pressure (molar water vapor content = 1.16%). B Calculated values *Derived data by calculation.
The higher heating value takes into account the latent heat of vaporization of water in the combustion products, and is useful in calculating heating values for fuels where condensation of the reaction products is practical (e.g., in a gas-fired boiler used for space heat). In other words, HHV assumes all the water component is in liquid state ...