found 10 matching terms.
| Term |
Definition |
| La |
Chemical symbol for Lanthanum. |
| Lap |
A defect appearing as a seam on a rolled bar. Laps are rolled over pieces of material that arise when a bar is given a pass through the rolls after a sharp overfill or fin has been formed, causing the protrusion to be rolled into the surface of the product. The presence of oxides usually prevents the lap welding to the original bar surface, so that in subsequent cold working it is carried through as a longitudinal crack. |
| L-D Process |
An oxygen steel making process named after the towns in Austria, Linz and Donawitz, where it was first developed. It is a modified Bessemer process, steel is produced in a solid bottom converter by injection of oxygen into the molten iron bath from a water cooled lance inserted through the converter mouth. Present day BOS (basic oxygen steelmaking) plants are developments of the L- D Process. |
| Leaded Steels |
When added to steel, lead does not go into solution but exists in a very finely divided state along the grain boundaries. It greatly assists machinability as it acts as a lubricant between the steel and the tool face. Lead is normally added in amounts between 0.15-0.35% and when combined with similar amounts of sulphur, optimum machinability is attained as in such steel as BS 970 230M07 Pb. |
| Li |
Chemical symbol for Lithium. |
| Limiting Range of Stress |
The greatest range of stress that a metal can withstand for an indefinite number of cycles without failure. If exceeded, the metal fractures after a certain number of cycles, which decrease as the range of stress increases. |
| Limiting Ruling Section |
The maximum diameter of cross section of a bar or component in which certain specified mechanical properties are achieved after heat treatment. |
| Limits |
A term used to determine a minimum and maximum. In a mechanism, it should denote the minimum and maximum sizes for each part, between which the parts will function properly in conjunction with each other and outside of which they will not. The words "limits" and "tolerances" are often interchanged, "tolerance" represents the difference between the minimum and maximum limits. |
| Limits of Proportionality |
The stress (load divided by original area of cross section of the test piece) at which the strain (elongation per unit of gauge length) ceases to be proportional to the corresponding stress. It is usually determined from a load-elongation diagram, obtained by plotting extensometer readings and is the stress at which the load-elongation line ceases to be straight. |
| Liquid Carburising |
A widely used method of case-hardening steel that eliminates scaling and the tendency to decarburisation and results in clean components. Sodium cyanide is the common media for this process, usually heated within the range of 900-930oC. It is advisable to pre-heat the components in neutral salts to avoid a temperature drop resulting from immersing cold components into the cyanide. After carburising, either single quench hardening or refining and hardening and tempering is carried out. |
