rolling forging

What are bulk deformation processes?

Metal forming operations that significantly change the shape of metal parts through plastic deformation.

What are the four basic bulk deformation processes?

Rolling, Forging, Extrusion, Wire and Bar Drawing.

What are the advantages of bulk deformation processes?

Large shape change, high production rate, improved mechanical properties, minimal waste.

What are the three starting forms for bulk deformation?

Cylindrical bars/billets, rectangular billets/slabs, and similar bulk shapes.

What are the three types of working temperatures in metal forming?

Cold working, Warm working, Hot working.

What is rolling?

A deformation process where metal thickness is reduced using compressive forces between rotating rolls.

What are the two main types of rolling?

Flat rolling and shape rolling.

What are the advantages of rolling?

High production rate, improved mechanical properties, close tolerances, smooth surfaces.

What are some products made by rolling?

Steel plates, I-beams, rails, bars, and sheets.

What are the different types of rolling mills?

Two-high, three-high, four-high, cluster, and tandem mills.

What is hot rolling?

Rolling done above the recrystallization temperature to improve ductility and grain structure.

What is cold rolling?

Rolling at room temperature for better surface finish, close tolerances, and increased strength.

What is spreading in rolling?

Increase in width of the strip due to lateral flow of metal.

What are common defects in rolling?

Wavy edges, zipper cracks, edge cracks, alligatoring.

What is tandem rolling?

A rolling process where multiple rolling stands are used in sequence to reduce thickness efficiently.

What is forging?

A process that deforms metal between dies to create desired shapes with improved mechanical properties.

What are the three main types of forging?

Open-die forging, impression-die forging, flashless (closed-die) forging.

What are the advantages of forging?

Higher strength, better grain flow, minimal material waste, high production rate.

What are the disadvantages of forging?

High equipment cost, limited shape complexity, requires secondary machining.

What is open-die forging?

A forging process where metal is compressed between flat dies, allowing lateral flow.

What is impression-die forging?

Forging where metal is compressed in a die cavity, forming flash that must be trimmed.

What is flashless forging?

A forging process where no excess material (flash) is formed, requiring precise volume control.

What is drop forging?

A forging process where a hammer delivers impact blows to shape the metal.

What are the types of forging hammers?

Gravity drop hammer, power drop hammer, counterblow hammer.

What are common forging defects?

Laps, cold shuts, cracks, internal voids.

What is extrusion?

A process where metal is forced through a die opening to create a uniform cross-sectional shape.

What are the two main types of extrusion?

Direct (forward) extrusion and indirect (backward) extrusion.

What are the advantages of extrusion?

Complex cross-sections, improved grain structure, high production rate.

What is hot extrusion?

Extrusion performed above the metal’s recrystallization temperature to reduce force requirements.

What is cold extrusion?

Extrusion performed at or near room temperature for better surface finish and material properties.

What is impact extrusion?

A high-speed cold extrusion process used for making thin-walled parts like aluminum cans.

What is hydrostatic extrusion?

An extrusion process where the billet is surrounded by pressurized fluid to reduce friction.

What are common extrusion defects?

Pipe defect, surface cracking, internal cracking.

What is wire and bar drawing?

A process where metal is pulled through a die to reduce its diameter and increase length.

What is the difference between wire drawing and bar drawing?

Wire drawing is for small diameters, bar drawing is for larger stock.

What are common applications of wire drawing?

Electrical wires, nails, bolts, rods, cables.

What are the advantages of drawing?

Good surface finish, increased strength, high production rates.

What are the steps in wire drawing?

Annealing, cleaning, pointing, lubrication, drawing, coiling.

What is a multi-stage drawing machine?

A machine with multiple dies and accumulators used for continuous wire drawing.

What are drawing defects?

Surface cracking, center cracking, poor lubrication issues.

What is thread rolling?

A process for forming screw threads on cylindrical parts by rolling them between dies.

What is ring rolling?

A process that enlarges the diameter of a thick-walled ring by reducing its wall thickness.

What is swaging?

A deformation process that reduces the diameter of rods or tubes using rotating dies.

What is roll piercing?

A process for making seamless tubes by creating an internal cavity in a solid billet.

What is pilger rolling?

A process that reduces the diameter and wall thickness of tubes.

What are forging presses?

Machines that apply gradual pressure instead of impact to deform metal.

What are the types of forging presses?

Mechanical press, hydraulic press, screw press.

What is coining?

A flashless forging process used to produce coins and detailed precision parts.

What is heading?

A forging process used to form heads on bolts, nails, and screws.

What is the difference between hot and cold forging?

Hot forging is done at high temperatures for better deformation; cold forging is done at room temperature for better strength.