1
Q
Manufacturing
A
- Converting some raw material into a useable product
2
Q
NDT of forgings
A
- Ultrasonic testing is used principally for the detection of internal discontinuities while MT and PT are use for detecting surface
3
Q
Blacksmithing
A
- when quantity of parts to be manufactured is smal and cost of tooling must be kept low, blacksmith or hammer forging may be used
- manual operation can only be used for light work and almost always performed hot
4
Q
Closed Impression Dies
A
- Work material is fully confined at least at the completion of the operation in a manner similar to casting except for the state of the material
5
Q
open Die forging
A
- metal is alternatively confined in different directions with the final result that 3D control is gained
5
Q
Drop and press forging
A
- Dies are not completely closed until the forging is completed with consequence that as dies are closed the metal may be squeezed to the parting line and be forced out of the die in some places before closing is complete
6
Q
Upsetting
A
- Enlarging the cross section by pressure from the end
7
Q
Drawing
A
- reducing the cross section of stock throughout
8
Q
Fullering
A
- Reducing the cross section of the stock between the ends
9
Q
Edging
A
- Distributing the metal to the general contour of the finished stock
10
Q
Blocking
A
- Shaping to rough finished form without detail
11
Q
Die Filling
A
- Excess metal forced into a gutter to ease all parts of the final cavity are filled. Excess metal called flash
- Flash must be removed in secondary operation generally trimming in a shearing type of die
12
Q
Drop forged/ press forged
A
- Steel is excuslively drop forged because of the large capacity presses that would be required for press forging and the shortening of the die life
- most nonferrous metals are press forged
13
Q
Roll forging
A
- useful when a cylindrical part is to be elongated throughout part of its length
14
Q
Hot rolling
A
- for materials that have little ductility and for large changes of section in any material, work is usually done hot to reduce th energy requirements and permit ductility recovery by recrystallization as deformation occurs
15
Q
Blooms, slabs, billets
A
- most material starts as cast ingots that are rolled into
- blooms and billets are square sections and slabs are rectangular
- designed for further deformation
16
Q
cast ingot discontinuities
A
- As much as 1/3 of the bloom may be cropped to eliminate impurities
- near surface discontinuities caused by ingots or rolling faults are removed by cropping, grinding, or scarfing
17
Q
Continuous casting eliminated ingots
A
- Billets smaller than blooms
- Continuous casting eliminates the making of ingots and their breakdown in the blooming mill
- Elimination of ingot cropping
18
Q
Continuous Hot rolling
A
- plate , sheet and rod shapes are in sufficient demand that many mills produce them in continuous mills
- Surface oxidation a problem, cleaning is often done by immersing the material in acid baths ( pickiling)
- limited accuracy in hot rolling
19
Q
Cold finishing
A
- Materials treated this way must have sufficient ductility but that ductility is reduced as the hardness, yield strength and tensile strength are increased
- Flat products of a steel mill are called strip, sheet, plate or bar, most are cold finished by rolling
- round stock may also be cold finished by rolling between skewed rollers in a process called turning or centerless ground for highest accuracy
20
Q
Pipe tubing/ mill products
A
- Pipe refers to a hollow product used to conduct fluids, tubing generally seamless
- most pipe made by welding process is steel
- some steel and all nonferrous tubular products are made by the seamless process
- if used in a high pressure application, NDT is involved
21
Q
Pipe by welding bell
A
- One of the oldest methods consists of drawing heated bevel edged skeletons in length of 20 to 40 feet through a welding bell
- Skelton is a term for wrought iron or steel that has been rolled or forged into narrow strips for pipe or tubing
22
Q
Pipe by roll welding
A
- method used for butt welding pipe in a continuos manner
23
Q
Resistance welded tubing
A
- light gage tubing in sizes up to 40cm ( 16in) in diameter may be [produced by resistance welding that has been formed cold by rolls
- materials heated only locally, pressure produces flash on both sides of the pipe forming rolls
24
Some pipe welded with filler metal
* for large sizes from about 15cm (6inches) to an unlimited upper limit. Pipe may be manufactured by forming plate or sheet and welding by any of the fusion processes, submerged arc- method often the most economical
* small quantity from 15 inches 30 inches in diameter is lap welded
25
Spiral welded pipe
* can be accomplished by resistance welding of continuous butt or lap joints
* light equipment required and flexibility in changing from one size to another
* any material that can be welded can be fabricated into pipe by the method
26
Seamless tubing
* seamless tubing; tubular product made without welding for steel involves piercing of round billets or large cross sections and short lengths
* subsequent deformation operations to control final diameter wall thickness and length
27
Sizing of seamless tubing
* Include reeling and rotary rolling, permit the inside diameter to be further enlarged with a reduction of wall thickness
* much seamless tubing is finished cold by rolling or drawing through dies with the advantages of improved tolerances and mechanical properties
28
Seamless tubing usefu for machine parts
* seamless is manufactured from nearly all the common grades of steel including carbon up to 1.5% AISI alloy steel and stainless steel
29
Press operation
* In cupping operations, seamless tubing is produced by a press type operation similar to shell drawing
30
Extrusion
* high degree of deformation required for extrusion, most metals are ductile enough for extensive extrusion only at high temps
* as a result the extrusion process is used primarily for shaping shapes of aluminum, copper, lead alloys and plastics
* electromagnetic testing techniques are most commonly applied to testing tubular products intended for high pressure applications
31
Drawing
* Involves not only bending but also stretching and compression of the metal over work areas
* shell drawing- flat blank is pushed through a round die to form a closed ended cup or shell
32
Stretch forming
* sheet to be formed is held under tension with sufficient force to exceed the yield point and pulled down over or wrapped around the single form block
* trimming allowances must be left and process restricted to shallow shapes with no re entrant angles
* Used for large parts ex. Large wing and body sections
33
Spinning
* one of the oldest methods for cylindrically drawn shapes
* most done cold
* wood most common form material. Most metals may be spun most of the cold
33
Rotary swaging
* are used most frequently for reducing the ends of bar tube, or wire stock so that it may be started through a die for drawing operation
* also used for closing or necking of cylinders for overall reduction of tubular products
33
Sheet- metal characteristics
* 1. Sufficient quantities to justify the high tooling cost that is required 2. Presence of Enough ductility in the material to permit plastic flow
* press working operations involve the failure of the metal by controlled loading, special tools high cost
34
Shearing
* operation of loading to fracture with opposed edges
* shear stresses applies to an internal load condition tending to slide one plane to another. Occur with practically all loading systems
* when external loads become great enough, the internal stresses will exceed critical values for the material and rupture will occur
35
Shearing categories 1. Stock preparation and blank producing operations
shearing, slitting, cutoff, parting, dinking, blanking
36
2 shearing operations : hole making operations
* punching, slotting, perforating, semi-notching, nor touring landing piercing
37
Shearing operations 3. Finishing operations
* Trimming shaving
38
Straight line shearing
* refers to straight line cutting performed on a squaring shear that has permanently mounted opposed straight blades
* may be used to reduce large sheets or coil stock to smaller size for holding purposes or produce parts with finished or semi finished shapes
39
Slitting
* rotary slitting which is primarily for reducing coil stock to narrower widths
40
Distortion during bending
* inside force is going to be compressive while outside force is going to be tensile. Think a bending of a pipe
41
Roll forming
* alternative to conventional bending
* used to make tubing, architectural trim and other similar parts in which a uniform cross section of relatively long length is necessary
42
Miscellaneous sheet metal forming proceses
* HERF- high energy rate forming
* most are low tooling cost methods, useful for low production quantites and most make use of a single forming surface insated of matching dies
* use some system that releases large amounts of energy in a short time
43
Explosive forming
* 1st method: sheet metal structures are forced by drawing, high explosives detonated in air or water at some predetermined distance. Pressures as high as 4,000,000 PSI are developed, shock waves in fluid transmit for work piece
2nd method: closed dies used and lower pressures about 40,000 PSI are developed by slower burning gas mixture useful for bulging operations
44
Electrical energy methods
* release of stored electrical energy though a coil near the workpiece
* principal uses has been in assembly of tubular componentes with end fittings
* electromagnetic forming or strictures repulsive forming
45
Powder metallurgy
* producing metal powders and objects shaped from individual mixed or alloyed metal powders by pressing to molding objects which may be simultaneously or subsequently heated to produce a coherent mass without fusion or with fusion of a low melting constituent only
46
Advantages of powdered metallurgy
* production of porous shapes obtained with lighter pressing pressures
* furnaces and techniques weren’t available only procedure was to press them into coherent masses and sinter at temp below the melting point point
47
Compaction of metal powder
* mechanical and atomic bonds established
* deformation increases contact area
* high temperature accelerates bonding
* most compaction is done along a single axis, opposing motions are used to reduce the effect at sidewalls friction on the density of compact
* density depends on particle size and shape, material, pressure time and the term depends on length to width or diameter ratio
48
Sintering
* mechanism by which solid particles are bonded by application of pressure or heat or both
* process involves welding, brazing, soldering, firing of ceramics and union of plastics granules
* non melting procedure, can be accomplished at room temp but most often at elevated temps
* hot pressing: appplication of heat and pressure
Cold pressing: application of heat after particles have been closely packed
48
Densities improved with hot pressing
* Hot pressing the plasticity of the particles is greater and recrystalize more readily, permitting higher densities to be achieved
* densities high enough can only be achieved by hot pressing
* require expansive die materials some a graphite die is used for each part
49
repressing/ coining
* parts that require close tolerances must always be finished by some dimensional treatment
* coining improves the density, strength, ductility of the material seldom that properties are equal to those produced by fusion
50
Conventional heat treatments
* not as effective on powder metallurgy due to the porous nature restricting the heat conductivity
* sometimes leads to resinteringl, for stabilization and homogeneity annealing for softness grain refinement for improved ductility hardening for improved heat resistance
* quench hardening for carbon steels, precipitation hardening for non ferrous, surface hardening by nitriding, carburizing, cynadizing
51
Impregnation
* properties improved by impregnation
* material used to impregnate is of much different density than the host compacted material
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