| This guy was walking along the beach in Malibu when he came across this salt-encrusted piece of metal. He worked for an hour or so to remove the salt. Lo and behold it was a very old oil lamp. The guy started to buff it to remove the verdigris when "... Read more of Commercial misfortune at Free Jokes.ca |  Informational.caPrivacy |
Steel MakingCritical PointsOne of the most important means of investigating the properti... Using Illuminating Gas The choice of a carburizing furnace depends greatly on the fa... Steel Worked In Austenitic State As a general rule steel should be worked when it is in the a... The Packing Department In Fig. 56 is shown the packing pots where the work is packe... Lathe And Planer Tools TO FORGE.--Gently warm the steel to remove any chill is parti... Preventing Carburizing By Copper-plating Copper-plating has been found effective and must have a thick... Heat Treatment Of Steel Heat treatment consists in heating and cooling metal at defin... Tensile Properties Strength of a metal is usually expressed in the number of pou... Placing The Thermo-couples The following illustrations from the Taylor Instrument Compan... Introduction Of Carbon The matter to which these notes are primarily directed is the... Hardening The forgings can be hardened by cooling in still air or quen... Flange Shields For Furnaces Such portable flame shields as the one illustrated in Fig. 1... Correction By Zero Adjustment Many pyrometers are supplied with a zero adjuster, by means ... Annealing Of High-speed Steel For annealing high-speed steel, some makers recommend using g... Pyrometers For Molten Metal Pyrometers for molten metal are connected to portable thermoc... Tungsten Tungsten, as an alloy in steel, has been known and used for a... Conclusions Martien was probably never a serious contender for the honor ... Cutting-off Steel From Bar To cut a piece from an annealed bar, cut off with a hack saw,... Forging High-speed Steel Heat very slowly and carefully to from 1,800 to 2,000 deg.F.... The Influence Of Size The size of the piece influences the physical properties obta... |
Preventing Cracks In HardeningCategory: HARDENING CARBON STEEL FOR TOOLS The blacksmith in the small shop, where equipment is usually very limited, often consisting of a forge, a small open hard-coal furnace, a barrel of water and a can of oil must have skill and experience. With this equipment the smith is expected to, and usually can, produce good results if proper care is taken. In hardening carbon tool steel in water, too much cannot be said in favor of slow, careful heating, nor against overheating if cracks are to be avoided. It is not wise to take the work from the hardening bath and leave it exposed to the air if there is any heat left in it, because it is more liable to crack than if left in the bath until cold. In heating, plenty of time is taken for the work to heat evenly clear through, thus avoiding strains caused by quick and improper heating, In quenching in water, contraction is much more rapid than was the expansion while heating, and strains begin the moment the work touches the water. If the piece has any considerable size and is taken from the bath before it is cold and allowed to come to the air, expansion starts again from the inside so rapidly that the chilled hardened surface cracks before the strains can be relieved. Many are most successful with the hardening bath about blood warm. When the work that is being hardened is nearly cold, it is taken from the water and instantly put into a can of oil, where it is allowed to finish cooling. The heat in the body of the tool will come to the surface more slowly, thus relieving the strain and overcoming much of the danger of cracking. Some contend that the temper should be drawn as soon as possible after hardening: but that if this cannot be done for some hours, the work should be left in the oil until the tempering can be done. It is claimed that forming dies and punch-press dies that are difficult to harden will seldom crack if treated in this way. Small tools or pieces that are very troublesome because of peculiar shape should be made of steel which has been thoroughly annealed. It is often well to mill or turn off the outer skin of the bar, to remove metal which has been cold-worked. Then heat slowly just through the critical range and cool in the furnace, in order to produce a very fine grain. Tools machined from such stock, and hardened with the utmost care, will have the best chance to survive without warping, growth or cracking. Next: Shrinking And Enlarging Work Previous: Hints For Tool Steel Users
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