Technical Information

Glossary of terms

Mechanical Properties of Steel - Condition, Strength, Hardness, Machinability

Chemical Composition - Steels, Alloys and Stainless

Surface Plating and Finishes

 

Glossary of terms

Mechanical Definitions

Cold working Deformation of a metal at room temperature without fracture which changes its shape and produces higher tensile strength

and machinability.

Ductility The ability of a metal to be deformed extensively under tension load without rupture or fracture. Ductility is expressed in terms of

percent elongation and percent reduction of area (e.g. drawn into wire).

Machinability The condition or property of a metal which allows it to be cut, turned, broached or formed by machine tools.

Malleability The ability of a metal to be deformed permanently under compression load without rupture or fracture (e.g. hammer or rolled into sheets.

Tensile strength The maximum load in tension (pulling apart or shearing) which a material can withstand before breaking or fracturing. Also known as the ultimate tensile strength (UTS) or maximum strength.

Work hardening Hardening that takes place through grain alignment when a metal is bent, rolled or hammered at room temperature. Not all metals work harden.

Yield Strength The maximum load at which a material exhibits a specific permanent deformation. Deformation to determine yield varies with material.

Heat Treating Definitions(back to top)

Annealing Heating and slow cooling to remove stresses, make steel softer, refine the structure, or change its ductility.

Carburizing Adding carbon to the surface of iron-based alloys by heating the metal below its melting point in contact with carbon-rich solids, liquids or gases.

Cyanide Hardening A method of case hardening which brings the metal surface in contact with the molten cyanide salt followed by a quenching.

Decarburization Removal of carbon from the surface of steel. This can occur through normal oxidizing action or as the result of heat treatment.

Drawing (Tempering) Reheating after hardening , held at a specific temperature and then quenched. This reduces hardening and increases toughness.

Hydrogen Embrittlement A condition where the surface finishing of metal (plating) results in a brittle outer case due to immersion in acid. Baking immediately following the plating process removes this brittle surface condition.

Nitriding A hardening process which adds nitrogen to a metal surface through contact with ammonia gas. Produces surface hardness (case) without quenching.

Precipitation Hardening A hardening process where certain metals are held at elevated temperature without quenching (age hardening).

Quenching Rapid cooling of steel by immersion in oil or water to fix its structure in a hardened state.

Sphereoidizing (anneal) Any process of heating and cooling steel that produces a rounded or globular form of carbide. This softens the metal, improving ductility.

Stress Relieve A low temperature heat treatment which removes stresses caused by cold working.

Thread series(back to top)

Thread series are groups of diameter-pitch combinations distinguished from each other by the number of threads per inch applied to a series of specific diameters. There are two general series classifications: standard and special.

Coarse Thread Series Applications

The coarse thread series (UNC/UNRC) is generally used for the bulk production of screws, bolts, and nuts. It is commonly used in relatively low strength materials such as cast iron, aluminum, magnesium, brass, bronze, and plastic because the coarse series threads provide more resistance to internal thread stripping than the fine or extra-fine series. Coarse series threads are advantageous where rapid assembly or disassembly is required, or if corrosion or damage from nicks due to handling or use is likely.

Fine Thread Series Applications

The fine thread series (UNF/UNRF) is commonly used for bolts and nuts in high strength applications. This series has less thread depth and a larger minor diameter than coarse series threads. Consequently, thinner walls are permitted for internal threads and more strength is available to external threads than for coarse series threads of the same nominal size.

8-Thread Series

The 8-thread series (8UN) is a uniform-pitch series for large diameters or as a compromise between coarse and fine thread series. Although originally intended for high-pressure-joint bolts and nuts, it is now widely used as a substitute for the coarse thread series for diameters larger than 1 inch.

12-Thread Series

The 12-thread series (12UN) is a uniform-pitch series for large diameters requiring threads of medium-fine pitch. Although originally intended for boiler practice, it is now used as a continuation of the fine thread series for diameters larger than 1-1/2 inch.

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Mechanical Properties of Steel

Stainless Steels

AISI

Materials Condition

Tensile Strength ksi

Yield Strength ksi

Hardness

Machinability % of CD1212

Permeability

Brinell

Rockwell

Annealed

Drawn

Type 302HQ

Annealed Bars

75-95

35-55

150-180

80-90B

60

Non-Magnetic

Non-Magnetic to Slightly

Type 303

Annealed Bars

85-95

30-40

160-180

83-95B

73

Non-Magnetic

Magnetic

Type 304

Annealed Bars

80-90

30-40

150-180

80-90B

45

Non-Magnetic

Slightly

Type 316

Annealed Bars

75-90

30-40

150-180

80-90B

40

Non-Magnetic

Non-Magnetic to Slightly

Type 410

Annealed Bars

70-100

35-45

150-200

80-90B

55

Magnetic

Magnetic

Type 416

Annealed Bars

80-100

55-65

190-220

90-95B

90

Magnetic

Magnetic

Type 17-4

Bars Cond. A

150

110

320

35C

45

Magnetic

Magnetic

Cond. H 900

200

185

415

44C

 

Cond. H 1025

170

165

352

38C

   

Stainless Steels

SAE No.

Machinability Rating

Condition

Range of Typical Hardness (Brinell)

4037

70

Annealed and Cold Drawn

174-217

8620

65

Hot Rolled and Cold Drawn

179-235

8630

70

Annealed and Cold Drawn

179-229

4130

70

Annealed and Cold Drawn

187-229

4140

65

Annealed and Cold Drawn

187-229

Carbon Steels - Rephosphorized & Resulphurized

Grade

Type of Processing

Estimated Minimum Values

Brinell
Hardness

Average Machinability Rating (Cold Drawn 1112-100%)

Tensile Strength
psi

Yield Strength
psi

1006

Hot rolled

43,000

24,000

86

 
 

Cold drawn

48,000

41,000

95

50

1008

Hot rolled

44,000

24,500

86

 
 

Cold drawn

49,000

41,500

95

55

1010

Hot rolled

47,000

26,000

95

 
 

Cold drawn

53,000

44,000

105

55

1018

Hot rolled

58,000

32,000

116

 
 

Cold drawn

64,000

54,000

126

70

1022

Hot rolled

62,000

34,000

121

 

1038

Cold drawn

69,000

58,000

137

70

1045

Hot rolled

82,000

45,000

163

 
 

Cold drawn

91,000

77,000

179

55

 

ACD

85,000

73,000

170

65

1212

Hot rolled

56,000

33,500

121

 
 

Cold drawn

78,000

60,000

167

100

12L14

Hot rolled

57,000

34,000

121

 
 

Cold drawn

78,000

60,000

163

160

1215

Hot rolled

57,000

34,000

121

 
 

Cold drawn

75,000

65,000

163

160

1117

Hot rolled

62,000

34,000

121

 
 

Cold drawn

69,000

58,000

137

90

1141

Hot rolled

94,000

51,500

187

 
 

Cold drawn

105,100

88,000

212

70

1144

Hot rolled

97,000

53,000

197

 
 

Cold drawn

108,000

90,000

217

80

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Chemical Composition

Grade

C

Mn

P Max.

S Max.

Si Max.

Ni

Cr

Mo Max.

Other Elements

Standard Carbon Steels

1006
1008
1010
1018
1022
1038
1045

 

.08 max.
10 max.
.08-.13
.15-.20
.18-.23
.35-.42
.43-.50

.25-.40
.30-.50
.30-.60
.60-.90
.70-1.00
.60-.90
.60-.90

0.040
0.040
0.040
0.040
0.040
0.040
0.040

0.050
0.050
0.050
0.050
0.050
0.050
0.050

         

?Resphosphorized & Resulphurized Carbon Steels

1117
1141
1144
12L14
1215

.14-.20
.37-.45
.40-.48
15 max.
.09 max

1.00-1.30
1.35-1.65
1.35-1.65
.85-1.15
.75-1.05

0.040
0.040
0.040
.04-.09
.04-.09

.08-.13
.08-.13
.24-.33
.26-.35
.06-.35

       



Pb(.15-.35)

Stainless Steel (Austenitic - Non-Magnetic)

302HQ
302
303
304
316

.10 max.
.15 max.
.15 max.
.08 max.
.08 max.

2.00 max.
2.00 max.
2.00 max.
2.00 max.
2.00 max.

0.045
0.045
0.045
0.045
0.045

0.030
0.030
.15 min.
0.030
0.030

1.00
1.00
1.00
1.00
1.00

8.00-10.00
8.00-10.00
8.00-10.00
8.00-10.50
10.00-14.00

17.00-19.00
17.00-19.00
17.00-19.00
18.00-20.00
16.00-18.00



0.60

2.00-3.00


 

Stainless steels (Martinsitic-Magnetic)

410
420

0.15
.15 min

1.00
1.00

0.04
0.04

0.03
0.03

1.00
1.00
 

 

11.50-13.50
12.00-14.00

   

Stainless Steel (Precipitation hardening Alloy)

17-4PH

0.07

1.00

0.04

0.03

1.00

3.00-5.00

15.50-17.50

 

Co + Ta (.15-.45)

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Surface Plating and Finishes

 

Finish

Color

For use on (material)

Corrosion resistance

Characteristics

Zinc (electroplated)

White to blue grey

all metals

good

Most commonly used plating. Good rust resisting qualities, appearance and low cost.

Cadmium (electroplated)

bright or dull silver grey

all metals

excellent

Superior rust resisting qualities. Used in marine and aviation applications. Relatively high cost and toxic to the environment.

Chromate

yellow, olive drab,
black, blue/white

 

zinc & cadmium
plated parts

 

very good

 

A secondary dipping process after plating that increases corrosion resistance, adding color or brilliance.

Dichromate

A combination of
yellow, brown, green or iridescent

 

zinc and cadmium
plated parts

 

very good

A secondary dip, same as chromate, only with rainbow appearance.

Black Zinc

black

all metals

very good

Shining black appearance with good rust-resisting qualities.

Black Oxide

black

 

ferrous metals and stainless steel

 

fair

A chemical discoloration which does not add to part thickness. Usually combined with an oil dip. Rust resistance comes from the oil only.

Phosphate & oil

 

charcoal grey or black

 


steel


good

Zinc or manganese phosphate used with a rust-inhibiting oil dip. Low cost.

Color Phosphate

 

blue, green, red,
purple, etc.

steel

very good

Chemically produced coating superior to regular phosphate and oil.

Iridite

olive drab, green, black, red, blue, bronze

all metals

good

Applied on top of zinc or cadmium plating as a die for color and additional corrosion protection.

Nickel

silver

all metals

very good

Hard stable finish, relatively expensive and sometimes hard to apply.

Chromium

bright blue/white

all metals

very good

Hard lustrous finish adds wear resistance and is very expensive.

Hot Dip Zinc
(galvanizing)

dull grey

all metals

very good

Parts are dipped in pure zinc. Gives maximum corrosion protection. Adds a thick irregular coating. Size must be adjusted to allow for thickness of coat.

Passivating

bright - etched

stainless steel

excellent

Parts are dipped in nitric acid which removes iron particles and brightens the finish. Produces a passive resistant finish.

Anodizing

frosty - etched

aluminum

excellent

Acid dip produces a hard oxide surface. Can be color dipped after anodizing for preferred finish.

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