what are the minimum requirements for quench hardening of a steel?
530133
Hardening of steel is obtained by a suitable quench from within or above the critical range. The temperatures are the same as those given for full annealing. The soaking time in air furnaces should be 1,2 min for each mm of cross-section or 0,6 min in salt or lead baths.
60842
Most austenitic stainless steel weldments do not require postweld heat treatment. ... Heavy sections in certain stainless steels (e.g. stabilised grades such as type 347) operating in the creep temperature range can suffer reheat cracking, and stress relief (>950°C) is the only guaranteed method of avoiding this problem.
701266
The typical TTT diagram is a C shaped curve. It shows the expected structures after various rates of cooling. The yellow arrows traces the cooling rate required for transforming austenite into pearlite, bainite or martensite.
245419
['Carbon – C. Carbon is added to iron to make steel. ... ', 'Silicon – Si. Silicon is added to carbon steels to help deoxidise, or kill, them. ... ', 'Manganese – Mn. ... ', 'Sulphur – S. ... ', 'Nitrogen – N. ... ', 'Niobium – Nb. ... ', 'Vanadium – V. ... ', 'Titanium – Ti.']
1076714
Machining is still possible without any great difficulty. A disadvantage of hardening and tempering lies in the fact that it is not always possible to attain optimum uniform microstructures because relatively large batches are treated in furnace systems and quenching baths at the same time.
1129857
Steel is less malleable and harder than mild steel. Mild steel s less brittle than steel. Steel is more resistant to corrosion. Mild steel can be further strengthened through the addition of carbon.
1379078
['Melting point: 660 °C (for AL 99,99 acc. to composition / alloying higher resp. lower)', 'Boiling point: 2500 °C (acc. to composition / alloying higher resp. lower)', 'Density: 2,70 g/cm³', 'Relative atomic mass 26,98.', 'Oxidation number: 3.', 'Atomic radius: 143,1 pm.', 'Ionic radius: 57 pm (+3)', 'Electrical conductivity: 36 m/Ohm·mm²']
1442101
Martensitic stainless steel is a specific type of stainless steel alloy that can be hardened and tempered through multiple ways of aging/heat treatment.
801569
Any laboratory experimentation with the matter requires a knowledge of chemical reactivity and physical properties. Knowledge of properties like malleability and ductility are needed when trying to make something out of a particular material.
1251203
Martensite is a body-centered tetragonal form of iron in which some carbon is dissolved. Martensite forms during quenching, when the face centered cubic lattice of austenite is distored into the body centered tetragonal structure without the loss of its contained carbon atoms into cementite and ferrite.
1069874
Tempering is a term historically associated with the heat treatment of martensite in steels. It describes how the microstructure and mechanical properties change as the metastable sample is held isothermally at a temperature where austenite cannot form. ... Any retained austenite may decompose during this stage.
405433
['density.', 'melting point.', 'thermal conductivity.', 'electrical conductivity (resistivity)', 'thermal expansion.', 'corrosion resistance.']
660238
Carbon steels Carbon steel, composed simply of iron and carbon, accounts for 90% of steel production. Low alloy steel is alloyed with other elements, usually molybdenum, manganese, chromium, or nickel, in amounts of up to 10% by weight to improve the hardenability of thick sections.
348157
Annealing involves heating steel to a specified temperature and then cooling at a very slow and controlled rate, whereas tempering involves heating the metal to a precise temperature below the critical point, and is often done in air, vacuum or inert atmospheres.
709883
Explanation: Stainless steels are hardened by constant heating and cooling and the best method suited for this alloy is electric butt welding. As soon as the stainless steel alloy is electric butt welded, it needs to be annealed at a temperature in between 750°C to 800°C.
413408
Tempering. Tempering is a low temperature (below A1) heat treatment process normally performed after neutral hardening, double hardening, atmospheric carburising, carbonitriding or induction hardening in order to reach a desired hardness/toughness ratio.
1349781
['Low alloyed Cr –Mo steel which has tensile strength (590-680) N/mm2.', 'Unalloyed Carbon Steel (Normalized).', 'Mild Steel (Cast throw).', 'Carbon Steel (forged or cast).', 'Nickel steel (forged).']