Stainless SteelStainless Steel

By: Dawn McCandlessBy: Dawn McCandless

Raw MaterialsRaw Materials

The materials that go into stainless steel are iron The materials that go into stainless steel are iron ore, chromium, silicon, nickel, carbon, nitrogen ore, chromium, silicon, nickel, carbon, nitrogen and manganese found in the earth’s surface and and manganese found in the earth’s surface and they are the basic elements. they are the basic elements.

Nitrogen, for instance improves tensile properties Nitrogen, for instance improves tensile properties like ductility.like ductility.

It also improves corrosion resistance which makes It also improves corrosion resistance which makes it valuable for use in duplex stainless steels.it valuable for use in duplex stainless steels.

Melting & Casting

• The raw materials are first melted together in an electric furnace. In this step it usually takes 8 to 12 hours of intense heat. When the melting is finished, the steel that is molten is cast into semi-finished forms.

• These include blooms (rectangular shapes), billets (round or square shapes 1.5 inches or 3.8 centimeters in thickness), slabs, rods, and tube rounds.

Forming

• Next, the semi-finished steel goes through forming operations, beginning with hot rolling, in which the steel is heated and passed through huge rolls. Blooms and billets are formed into bar and wire, while slabs are formed into plate, strip, and sheet.

Heat Treatment Heat Treatment

After the stainless steel is formed, most After the stainless steel is formed, most types must go through an annealing step. types must go through an annealing step. Annealing is a heat treatment in which Annealing is a heat treatment in which the steel is heated and cooled under the steel is heated and cooled under controlled conditions to relieve internal controlled conditions to relieve internal stresses and soften the metal. stresses and soften the metal.

Descaling

• Annealing causes a scale or build-up to form on the steel. The scale can be removed using several processes. One of the most common methods, pickling, uses a nitric-hydrofluoric acid bath to descale the steel.

Cutting

• Mechanical cutting uses straight shearing guillotine knives.

• Circle shearing uses circular knives horizontally and vertically positioned

• Sawing using high speed steel blades, blanking, and nibbling.

• Blanking uses metal punches and it dies to punches out the shape

• Nibbling is the process of cutting by blanking out a series of overlapping holes.

Finishing

• Look at this picture it shows the steps on how it is finished.

End userEnd user

►After the stainless steel is in various After the stainless steel is in various forms it is then packed and shipped to forms it is then packed and shipped to the fabricator or end user.the fabricator or end user.

►Further shaping is required and it is Further shaping is required and it is done by rolling, pressing, forging, done by rolling, pressing, forging, press drawing, and extrusion.press drawing, and extrusion.

►Heat treating, machining, and cleaning Heat treating, machining, and cleaning processes are also often required.processes are also often required.

Renewable or NonrenewableRenewable or Nonrenewable

► Iron ore is nonrenewableIron ore is nonrenewable►Silicon is a renewable resourceSilicon is a renewable resource►Nickel is nonrenewableNickel is nonrenewable►Carbon is nonrenewableCarbon is nonrenewable►Chromium is nonrenewable because it Chromium is nonrenewable because it

has to be mined.has to be mined.►Manganese is a renewable resource.Manganese is a renewable resource.►Nitrogen is nonrenewable.Nitrogen is nonrenewable.

RecyclingRecycling

►Stainless steel is 100% recyclable.Stainless steel is 100% recyclable.