METAL FABRICATION AND HOW TO DISTINGUISH METAL TYPES
Custom metal fabricators must be able to identify particular alloy types from within larger groups of the same metal material. Particular alloys are selected for use because they exhibit characteristics suitable for the desired end method of fabrication. When a part of aluminium sheet or steel unexpectedly cracks during the forming operation or cannot be properly welded the shop not only experiences a loss in material cost but also a loss in the hours of labour that went into the part. Up to that point end-use failure or failure of the part in service can cause the loss of virtually thousands of dollars in associated equipment as well as the loss of human life. Many custom metal fabricators and other fabrication companies require that materials are certified as to allow content analysis. The Certificate of Compliance is part of the commendation procedure that follows a plate or sheet of rose stock from the manufacturer’s mill through the distributor's warehouse to the fabricator, and finally to the end user purchaser. Fabricating shops usually purchase just a few alloy types off still, aluminium and add materials depending on the product lines and needs. Most of the material, but not all is delivered with some sort of identifying labels or coding, it depends largely on the source and to some extent the type of material domestically manufactured. Material from the better-known mills usually carries identifying stencils repeated at intervals across the stock while, many imported materials do not.
Additionally, many imported metal materials do not exhibit the exacting alloy content of the better-known domestic metal materials. When a shop is fabricating to specific code requirements such as government or military the specific alloy content is often specified. Steel purchased as a universal mill plate might be adequate for commercial application however, the shop must be sure that the material it is fabricating conforms to an American Society of testing in materials ASTM standard for government or military use.
Steel metal alloys
Alloy and tool steels often carry coding to identify each specific type, but this code is not common to all manufacturers. Shop personnel must make sure they are using any processing stock that will perform as expected during both metal fabrication and in end-use.
The various still alloys can be identified by several methods. The most common is the spark test. Department of Sparks from of can be used to identify several Distinct alloy types as well as types of cast iron. However, the best use of the grinding wheel is in comparing the unknown material with the spike pattern of the known sample. A magnet can also be used to distinguish between stainless in other types of steel. However, this test is not conclusive as not all stainless is no non-magnetic. Of course, the magnet can be used to Differentiate. Between ferrous and nonferrous metals, when weight and appearance are not that easily discernible.
Fracture in the cheap examination is also an acceptable method but is not always practical.
Aluminium alloys
How can aluminium fabricators distinguish aluminium from other metals?
Various grades of aluminium are distinguishable from one another by analysing the amount of flexibility, one can also determine the hardness or softness of the alloy. The examination of a sheet edge can also identify another group. During the chemical baths used to clean aluminium for either welding or feather finishing, certain types of alloys exhibit distinct chemical reactions. The silicone magnesium alloy 6061 shows a dark grey film when the chemical etchant acts on its oxide coating. Alloys in the 5000 series acquired distinct like a great film, while the copper-based alloys turn yet black. This film is removed in subsequent baths. The purer Aluminium Alloys (1100 series) show no change in appearance after emerging in the cleaning solution.
Magnesium metal alloys
The various alloy types are almost impossible to identify visually. Physical tests can be employed in the shop and are also inconclusive. When the lighter weight of magnesium is not really readily apparent when compared with aluminium, these two similar appearing materials can be identified by catching a small number of fillings in the centre of a piece of paper and spreading them out. When the paper is lit with a match, the magnesium feelings will begin to flare brightly as the flame reaches them.
The importance of metal identification in custom metal fabrication
If material is delivered to the shop without stencilling or labelling. It should be identified immediately and marked us two alloy types and thicknesses. A well-organised shop has stock storage facilities that keep the various materials separated until they are needed. In addition, and most importantly provisions must be made to identify and store drop-off or leftover random pieces. Many custom fabrication studios have either beans or barrels for this purpose and depend on the conscientious effort of the employees to keep these less than full-size, pieces separated.
Custom metal fabricators should make some effort to verify that the materials they selected is what it is supposed to be. Cutting off a small piece and attempting to bend, punch or drill it might reveal an error In labelling that could save many dollars in time and material. Newly hired employees should make an immediate effort to become familiar with the types of material used in the shop and how they are catalogued and stored.