Manufacturing Processes for Ferrous Metals

The forging process is specifically used to change the workpiece’s size and shape by compressing or heating it in the whole process. It helps to make different kinds of shape, which is used in various manufacturing industries.

What is the difference between hot and cold forging?

How are the properties changed?

Rolling of steel is a metal forming process in which steel is passed through a pair of rotating rolls for plastic deformation of the steel. Plastic deformation is caused by the compressive forces applied through the rotating rolls.

Can you label the microstructure of hot and cold rolled steel?

Sand casting, known as sand molding casting, is a casting process that uses sand as a mold. Then pour the liquid metal into this mold to create a casting part.It is one of the oldest casting processes. It can be used to make metal components of all sizes, ranging from 1kg to hundred tons.

Can you give some possible defects from sand casting?

Continuous casting, also referred to as strand casting, is a process used in manufacturing industry to cast a continuous length of metal. Molten metal is cast through a mold, the casting takes the two dimensional profile of the mold but its length is indeterminate. The casting will keep traveling downward, its length increasing with time. New molten metal is constantly supplied to the mold, at exactly the correct rate, to keep up with the solidifying casting. Industrial manufacture of continuous castings is a very precisely calculated operation.

Shell molding, also known as shell-mold casting, is an expendable mold casting process that uses resin covered sand to form the mold. As compared to sand casting, this process has better dimensional accuracy, a higher productivity rate, and lower labour requirements. It is used for small to medium parts that require high precision.

It works on basic principle of centrifugal force on a rotating Component. In this process, a mould is rotated about its central axis when the molten metal is poured into it. A centrifugal force acts on molten metal due to this rotation, which forces the metal at outer wall of mould. The mould rotates until the whole casting solidifies.

Die casting is a metal casting process that is characterized by forcing molten metal under high pressure or gravity into a mould cavity. The mould cavity is created using two hardened tool steel dies which have been machined into shape and work similarly to an injection mould during the process.

Investment casting is an industrial process based on lost-wax casting, one of the oldest known metal-forming techniques. The term "lost-wax casting" can also refer to modern investment casting processes.

Full-mold casting is an evaporative-pattern casting process which is a combination of sand casting and lost-foam casting. It uses an expanded polystyrene foam pattern which is then surrounded by sand, much like sand casting. The metal is then poured directly into the mold, which vaporizes the foam upon contact.

After going through this process the properties of the material used are altered. Its hardness and yield strength are increased, cross-sectional area is decreased, some residual surface stresses will be present and micro cracks may appear. Physical and chemical properties are only influenced slightly.

Powder metallurgy (sintering) is a metal-forming process performed by heating compacted metal powders to just below their melting points.

Sintering is a heat treatment process in which a large quantity of loose aggregate material is subjected to a sufficiently high temperature and pressure to cause the loose material to become a compact solid piece. The amount of heat and pressure administered during the sintering process is slightly less than the material's melting point.

Draw a neat sketch of this diagram. Can you identify the grain structure for this weld?

Hint: columner grains, equiaxed grains and elongated grains.Why do the equiaxed grains differ in size?

Chromoly is an abbreviation for "chromium-molybdenum.” Chromium is classified as a transition metal on the periodic table and is known for its resistance to corrosion; Molybdenum is an element known for its strengthening properties and resistance to temperature fluctuations.

When combined, these elements form a specific alloy that is creep-resistant, meaning that unlike standard steel or aluminum, it won’t deform or shift over time. This alloy is also extremely strong; it can put up with a lot more bumps and bruises than aluminum, and rivals industrial steel when it comes to a general lifespan.

In summary, chromoly steel is lighter than regular steel, more flexible than aluminum, more cost efficient than titanium, and the perfect material for your bike.