| In the chair which stood before the writing-table in the middle of the room sat the figure of Lord Clarenceux. The figure did not move as I went in; its back was towards me. At the other end of the room was the doorway, which led to the sm... Read more of The Ghost Of Lord Clarenceux at Scary Stories.ca |  InformationalPrivacy |
Steel MakingAnnealing To Relieve Internal StressesWork quenched from a high temperature and not afterward tempe... The Pyrometer And Its Use In the heat treatment of steel, it has become absolutely nece... Quality And Structure The quality of high-speed steel is dependent to a very great ... Shrinking And Enlarging Work Steel can be shrunk or enlarged by proper heating and cooling... Pyrometers Armor plate makers sometimes use the copper ball or Siemens' ... Heat Treatment Of Steel Heat treatment consists in heating and cooling metal at defin... Hints For Tool Steel Users Do not hesitate to ask for information from the maker as to t... Vanadium Vanadium has a very marked effect upon alloy steels rich in c... Tungsten Tungsten, as an alloy in steel, has been known and used for a... Leeds And Northrup Optical Pyrometer The principles of this very popular method of measuring tempe... Detrimental Elements Sulphur and phosphorus are two elements known to be detrimen... Heat Treatment Of Milling Cutters Drills Reamers Etc THE FIRE.--Gas and electric furnaces designed for high heats ... The Modern Hardening Room A hardening room of today means a very different place from ... Steel Before The 1850's In spite of a rapid increase in the use of machines and the ... Oil-hardening Steel Heat slowly and uniformly to 1,450 deg.F. and forge thorough... Temperatures To Use As soon as the temperature of the steel reaches 100 deg.C. (... Quenching It is considered good practice to quench alloy steels from th... Impact Tests Impact tests are of considerable importance as an indication ... Case-hardening Treatments For Various Steels Plain water, salt water and linseed oil are the three most co... For Milling Cutters And Formed Tools FORGING.--Forge as before.--ANNEALING.--Place the steel in a ... |
Carburizing MaterialCategory: CASE-HARDENING OR SURFACE-CARBURIZING The simplest carburizing substance is charcoal. It is also the slowest, but is often used mixed with something that will evolve large volumes of carbon monoxide or hydrocarbon gas on being heated. A great variety of materials is used, a few of them being charcoal (both wood and bone), charred leather, crushed bone, horn, mixtures of charcoal and barium carbonate, coke and heavy oils, coke treated with alkaline carbonates, peat, charcoal mixed with common salt, saltpeter, resin, flour, potassium bichromate, vegetable fibre, limestone, various seed husks, etc. In general, it is well to avoid complex mixtures. H. L. Heathcote, on analyzing seventeen different carburizers, found that they contained the following ingredients: Per cent Moisture 2.68 to 26.17 Oil 0.17 to 20.76 Carbon (organic) 6.70 to 54.19 Calcium phosphate 0.32 to 74.75 Calcium carbonate 1.20 to 11.57 Barium carbonate nil to 42.00 Zinc oxide nil to 14.50 Silica nil to 8.14 Sulphates (SO3) trace to 3.45 Sodium chloride nil to 7.88 Sodium carbonate nil to 40.00 Sulphides (S) nil to 2.80 Carburizing mixtures, though bought by weight, are used by volume, and the weight per cubic foot is a big factor in making a selection. A good mixture should be porous, so that the evolved gases, which should be generated at the proper temperature, may move freely around the steel objects being carburized; should be a good conductor of heat; should possess minimum shrinkage when used; and should be capable of being tamped down. Many secret mixtures are sold, falsely claimed to be able to convert inferior metal into crucible tool steel grade. They are generally nothing more than mixtures of carbonaceous and cyanogen compounds possessing the well-known carburizing properties of those substances. Next: Quenching Previous: Rate Of Absorption
Viewed 1176 |
||||||||||||||||||||
