MECH 3503 - General - Midterm Review

• The application of physical and chemical processes
• to alter the geometry, properties, and/or
• appearance of a given starting material to make
• parts or products
• • It also includes assembly of multiple parts to make
• products

• The transformation of materials into items of
• greater value by means of one or more processing
• and/or assembly operations
• • Manufacturing adds value

Processing + Assembly

Processing operations - altering the geometry of the starting work material

Processing operations - improve the physical properties of the material without changing its shape

Processing operations - performed to clean, treat, coat, or deposit material onto the surface of the work

• 1. Solidification - starting material is a heated liquid for semifluid that cools and solidifies to form part geometry
• 2. Particulate - starting material is a powder, and the powders are formed to create geometry and heated to strengthen
• 3. Deformation - starting material is a ductile solid (commonly metal) that is deformed to shape part
• 4. Material removal - starting material is a solid (ductile or brittle) from which material is removed so that what remains has the desired geometry

Starting material is a heated liquid for semifluid that cools and solidifies to form part geometry

starting material is a powder, and the powders are formed to create geometry and heated to strengthen

Starting material is a ductile solid (commonly metal) that is deformed to shape part

Starting material is a solid (ductile or brittle) from which material is removed so that what remains has the desired geometry

• A subsection of manufacturing, processing operations
• Involve heat treatments such as: annealing and strengthening processes performed on metals and glasses or sintering of powdered metals ad crystalline ceramics

• A subsection of manufacturing, processing operations
• Involve:
• 1. cleaning
• 2. surface treatments (e.g. sand blasting, diffusion)
• 3. Coating and thin-film deposition - applying a coating to the exterior surface of the work (e.g. electroplaing, painting)

• Subsection of manufacturing
• 1. Joining processes to form permanent joints (e.g. welding, brazing, soldering)
• 2. Mechanical assembly (threaded fasteners, rivets)

• A category of materials characterized by...
• 1. Ductility
• 2. Malleability
• 3. Luster
• 4. High electrical and thermal conductivity

Generally characterized as ferrous (steels and cast irons) and nonferrous (aluminum, copper)

Increase tensile strength and hardness

Iron alloys containing from 2.1% to about 4% carbon and from 1% to 3% silicon

Iron-carbon alloy containing 0.02%-2.11% carbon (mostly 0.05% and 1.1%)

Plain carbon steel - just carbon and steel

Low alloy steel - has small amounts of alloys like manganese

Stainless steel - chromium, doesn't rust or oxidize due to oxidizing layer

Tool steel - really hard steel used for our molding

• - Carbon is principal alloy element 
• - Strength of plain carbon steel increases with carbon content, but ductility is reduced
• - High carbon steels can be heat treated to form martensite, making the steel very hard and strong

• Less than 0.20% C
• Used for automobile sheetmetal parts, plate steel for fabrication, railroad rails

• Between 0.20% and 0.50% C
• Used for machinery components and engine parts such as crankshafts and connecting rods

• Greater than 0.50%
• Springs, cutting tools and blades, wear-resistant parts

Iron-carbon alloys containing additional alloying elements in amounts totaling less than ~ 5% by weight

Mechanical properties to plain carbon steels better

Low alloy steels 

• Higher strength, hardness, hot hardness, wear
• resistance, and toughness
• ▪ Heat treatment is often required to achieve these
• improved properties

• Principal alloying element is chromium, usually greater than 15%
• Can also use Ni 
• High C reduces corrosion protection since chromium carbide forms 
• High strength and ductility, but difficult to work in manufacturing
• More expensive than plain C

• Austenitic stainless - typical composition 18% Cr
• and 8% Ni
• 2. Ferritic stainless - about 15% to 20% Cr, low C,
• and no Ni
• 3. Martensitic stainless - as much as 18% Cr but no
• Ni, higher C content than ferritic stainless

True

False

Iron alloys containing from 2.1% to about 4% carbon and from 1% to 3% silicon

• ALUMINUmUMUMUMUMUMUMU
• Copper
• Magnesium
• Nickel
• Titanium
• Zinc

• High-performance alloys designed to meet demanding
• requirements for strength and resistance to surface
• degradation at high service temperatures

High temperature performance is EXCELLENT! 

Three or more metals

• Iron-based alloys - in some cases iron is less than 50%
• of total composition
• ▪ Alloyed with Ni, Cr, Co
• 2. Nickel-based alloys - better high temperature strength
• than alloy steels
• ▪ Alloyed with Cr, Co, Fe, Mo, Ti
• 3. Cobalt-based alloys -  40% Co and  20% chromium
• ▪ Alloyed with Ni, Mo, and W
• ▪ Virtually all superalloys strengthen by precipitation
• hardening

Magnesium

• Nickel is more corrosion resistant
• High temperature properties of Ni alloys are superior

True

False

For corrosion resistant components such as marine components and prosthetic implants

Low melting point makes it good as a casting metal, esp die casting

Corrosion protection when coated onto steel or iron