Volume 05 - Surface Engineering Part 14 pdf

Table 6 Equipment and operating conditions for high-luster buffing of aluminum productsBuffing wheel Diameter Size Wheel speed Product m/s sfm Type of compound Production, pieces per hou

Table 5 Conditions of belt polishing for bright finishing aluminum die-cast soleplates

Operation Area

polished

Polishing head, No.

Type

Hardness, durometer

Abrasive mesh size

Life, pieces

Table 6 Equipment and operating conditions for high-luster buffing of aluminum products

Buffing wheel

Diameter Size

Wheel speed Product

m/s sfm

Type of compound

Production, pieces per hour

Table 7 Sequence and conditions of automatic buffing operations for obtaining specular finish on aluminum frying-pan covers

Type

mm in mm in mm in.

Ply Thread count

Density No of

sections

m/s sfm

Life, pieces

No

of guns

On Off

g per shot

oz per shot

Table 8 Automatic bright-finish buffing of aluminum soleplates

Operation Area

buffed

Buffing head No.

Type Size

mm in mm in.

No of sections

m/s sfm

Life, pieces

No

of guns

g per shot

oz per shot

Table 9 Methods, equipment, and conditions for mechanical satin finishing of aluminum

Suitable equipment Speed Method

Buffing lathe

Portable power head

Power required

Lubricant

•

Etching cleaners

Nonetching cleaners

Constituents Composition, %

Solution A

Solution B

Table 11 Acid cleaners used to clean aluminum surfaces

Constituent or

condition

Amount or value

Solution 1

Solution 2

Solution 3

Solution 4

Solution 5

Constituent or condition Range

Phosphoric-nitric (a)

Phosphoric-acetic-nitric (c)

Table 12 Electrolytic brightening and polishing solutions and processes for use on aluminum and aluminum alloys

density

Film thickness Bath Percentage

°C °F

Duration, min

Voltage, V

A/dm 2 A/ft 2

m mils

Appearance properties

Remarks

Seignette salt brightener (alkaline process)

Acid brightening

VAW brightener

Smudge remover

Smut removal (a)

Sealing

Table 15 Sulfuric-phosphoric-chromic acid electrobrightening of aluminum and aluminum alloys

Sealing

Effect of time on the amount of metal removed from aluminum alloys during alkaline etching (a) By micrometer measurement (b) Calculated from loss in weight Both solutions contain 5 wt% NaOH at 70 ± 5 °C (160 ± 5 °F)

Solution 1

Solution 2

Solution 3

Operations used in etching of aluminum and aluminum alloys

Oxide conversion coatings

Phosphate conversion coatings

Chromate conversion coatings

Table 17 Process conditions for oxide conversion coating of aluminum

Amount Temperature Process Bath

composition

g/L oz/gal °C °F

Duration, min

Uses

Specific formulations

Desired operating range

Table 18 Process conditions for chromate conversion coating of aluminum

μΩ μΩ

Reason for plating

Automotive applications

Aircraft applications

Electrical and electronics applications

General hardware

Household appliances

Personal products

Table 20 Conditions for anodizing aluminum alloys prior to electroplating

Temperature Alloy (a) Specific

gravity

Voltage Time,

min

Operating temperature

Alloys 1100 and 3003

Alloys 413, 319, 356 and 380

Preplating surface preparation procedures suitable for wrought aluminum alloys that contain high amounts of silicon or do not contain interfering microconstituents (e.g., 1100 and 3003) and for aluminum casting alloys 413, 319, 356, and 380

Operating temperature

Preplating surface preparation procedures suitable for all wrought aluminum alloys, for most aluminum casting alloys, and for magnesium-containing aluminum alloys with interfering microconstituents Applicable alloys include 1100, 3003, 3004, 2011, 2017, 2024, 5052, 6061, 208, 295, 319, and 355

°C °F

s

Preplating surface preparation procedures suitable for most aluminum casting alloys, for wrought aluminum alloys containing less than approximately 3% Mg (e.g., 1100, 3003, 3004, 2011, 2017, 2024, 5052, and 6061), and for aluminum alloys whose identities are not known

Table 21 Zincating solutions for use with aluminum alloys

Sodium

hydroxide

Zinc oxide Ferric

chloride crystals

Rochelle salt Sodium

nitrate

Operating temperature

Solution

type

g/L oz/gal g/L oz/gal g/L oz/gal g/L oz/gal g/L oz/gal °C °F

Processing time,s

Table 22 Conditions for electroplating various metals on zincated aluminum surfaces

Minimum deposit

Bath temperature Current density Electroplate

Plating time, min

Type of electrolyte

m

μ

Phosphate enamel

Composition of solution Operating

temperature

No Type

Cycle time, min

Process for preparing heat-treatable aluminum alloys for porcelain enameling

μ μ

Table 24 Cycles for firing procelain enamel on aluminum

Firing temperature

Type of

part

Section thickness, 0.025 mm (0.001 in.)

Firing time, min

°C °F

Table 25 Designations for aluminum finishes

Mechanical finishes M

Chemical finishes C

Anodic coatings A

Resinous and other organic coatings R

Vitreous (porcelain and ceramic) coatings (d) V

Electroplated and other metal coatings E

Laminated coatings (d) L

μ

• Coppers,

• High-copper alloys,

• Copper-zinc alloys (brasses),

• Copper-tin alloys (phosphor bronzes),

• Copper-aluminum alloys (aluminum bronzes),

• Copper-silicon alloys (silicon bronzes),

• Copper-nickel alloys,

• Copper-zinc-nickel alloys (nickel silvers),

• Special alloys,

Pickling and Bright Dipping

Table 1 Pickling conditions for copper-base materials Constituent or condition Amount or value

Sulfuric acid bath

Hydrochloric acid bath

Table 2 Scale dip and bright dip conditions for copper-base metals

Hydrochloric acid (c) Solution Sulfuric acid,

vol% (a)

Nitric acid, vol% (b)

g/L oz/gal

Water, vol%

Immersion time,s

Table 3 Pickling conditions for copper alloys containing silicon

Constituent or

condition

Solution A Solution B

Small Medium Large

Solution Tank material

Table 5 Equipment requirements for pickling brass tubes or rods

Temperature Tanks (a) Material Solution

Overflow (b)

Abrasive Blast Cleaning

Size of abrasive particles

Tumbling time, h

Finish

Heavy cutting

Moderate cutting

Light cutting (a)

Table 7 Operating conditions for bright rolling or water rolling

Table 8 Operating conditions for cleaning and pickling in water rolling barrels

Temperature Solution Concentration

Table 9 Operating conditions for vibratory finishing

Ratio of medium

to parts (a)

Vibrations per min

Time, min

Purpose

Polishing and Buffing

Wheel speed Finish

m/min ft/min

Table 10 Offhand belt polishing and wheel buffing operations for sand cast red brass parts

Operation Type of contact wheel Wheel

speed, rev/min

Pieces per hour

Type of abrasive belt

Belt life, pieces

Polishing lubricant

or buffing compound

• Wire wheels

• Emery cloth or paper

• Polishing wheels headed with greaseless compounds

• Soft tampico and manila brushes

Table 11 Suggested sequence of operations for scratch brushing of copper alloy parts

Size of wheel

Speed, rev/min

Chemical and Electrochemical Cleaning

Table 12 Cycles for cleaning copper alloy parts with a solvent cleaner

Temperature of solvent

Part Solvent cleaner

Immersion time, min

Soil removed

Table 13 Compounds used for formulating alkaline cleaners

%

Electrolytic cleaners,

%

μ

Operating temperature

Surface preparation required for removal of buffing compounds and tarnish before plating of copper

alloys If the buffing compound is hard and dry, an additional presoak in a solvent emulsion cleaner can be used

Operating Temperature

Surface preparation required for the removal of buffing compounds and for bright dipping before plating

of copper alloys

Composition

of solution

Operating temperature

Cycle time, s

Surface preparation of brass powder metallurgy parts before plating

Gold plating

Silver plating

Decorative chromium deposits

μ μ

Hard chromium deposits

μ μ

Table 14 Bath compositions and operating conditions for tin-lead plating

Total tin Stannous tin Lead Free fluoboric acid Free boric acid Peptone

Constituent

g/L oz/gal g/L oz/gal g/L oz/gal g/L oz/gal g/L oz/gal g/L oz/gal

Anode Composition

•

•

• Composition of the material

• Condition of the initial surface

• Grain size of the metal

Ingredient Parts by weight

Table 15 Solutions for coloring copper alloys

Desired

color

Solution composition Process conditions Comments

Solutions for alloys containing ≥85% Cu

≤

≤

Solutions for alloys containing <85% Cu

μ μ

•

•

•

Revised by James E Hillis, Dow Chemical Company

μ

Ten-day ASTM B 117 salt-spray corrosion performance of high-purity AZ91D (0.1 mm/yr, or 4 mils/yr, left) versus AZ91B (17 mm/yr, or 680 mils/yr, right) Source: Ref 3, 6

Five-year Gulf Coast corrosion performance of coated AZ91D die cast magnesium (left) versus rolled carbon steel (right) Both panels were cleaned, iron phosphatized, coated with 18 μm (0.7 mil) of baked cathodic epoxy primer and 12 to 20 μm (0.5 to 0.8 mil) of acrylic lacquer The test was conducted at the ASTM Brazos River site near Freeport, TX using scribed panels per ASTM D 1654 Source: Ref 1

cold-Table 1 Finishing systems applied to magnesium for various applications

Systems for specific parts

μ

General systems indoor exposures

Proc Int Magnesium Assoc.

Annual Book of ASTM Standards,

Table 2 Acid pickling treatments for magnesium alloys

Solution Metal

Tank material

or lining

For cast or wrought alloys

For wrought alloys only

For cast alloys only

°C (°F)

Cycle time, min

Tank material

μ

μμ

Chrome pickle treatment (chemical treatment No 1; MIL-M-3171, type I) Applicable to all alloys and product forms Used to provide a base for paint or short-time protection for shipment or storage

°C (°F)

Cycle time, min

Tank material

μμ

Sealed chrome pickle treatment Applicable to all alloys and product forms Used as a substitute for dichromate coating or for more protection than is provided by the chrome pickle treatment

Corrosion, ASM Handbook,

Table 3 Procedures for polishing and buffing magnesium alloys

Wheel

Operation Abrasive

grit size

Type

Proc Int Magnesium Assoc.

Tank material

Dichromate treatment (chemical treatment No 9; MIL-M-3171, Type III) Used for maximum corrosion protection and to provide a paint base Results in no appreciable change in dimensions and can be used on finish-machined wrought and cast products of all alloys except EK30A, EK41A, HK31A, and M1A

°C (°F)

Cycle time, min

Tank material

Annual Book of ASTM Standards,

μ

Operating temperature,

°C (°F)

Cycle time, min

Tank material

Chemical treatment No 9 (MIL-M-3171A) galvanic anodizing

μ μ

Direct current treatment

For coatings of both colors and thicknesses

For light green coating, thin

For dark green coating, thick (e)

Sealing post-treatment (g)

Anodizing

Bath Replenishment.

Post-Treatment.

Equipment.

Type of coating Operating conditions

Green (a) Black (b)

Proc Int Magnesium Association

Proc Int Magnesium Association

Table 4 Effects of lack of control of process variables in acid pickling, chemical, and anodic treatments

Effect of operating out of recommended range

constituent

or condition

Recommended range

Acid pickling treatments

Chemical treatments

Anodic treatments

Table 5 Causes and corrections of difficulties with coatings produced by the chrome pickle and sealed chrome pickle treatments

Table 6 Causes and corrections of difficulties with dichromate coatings

Table 7 Causes and corrections of difficulties with coatings produced by anodizing treatments

Chemical treatment No 9 (a)

Chemical treatment No 17

HAE anodizing treatment (f)

• Abrasion resistance:

• Salt spray (fog) exposure:

μ

Cycle time, min

Tank material

Preparing magnesium alloys for nickel plating

μ

Solution temperature Operation Cycle time,

operating conditions

Alkaline cleaning,

Acid Pickling.

Surface Activation.

Zinc Immersion Coating.

Table 8 Composition of zinc immersion bath

Concentration

Nominal Range Activator Constituent

g/L oz/gal g/L oz/gal

Copper strike plating

μ

Table 9 Minimum total plate thicknesses for decorative chromium plating

Wrought alloys

Cast alloys

Service

environment

μm mils μm mils

Zinc immersion deposits

Chromium

Copper

Nickel

Copper, nickel, tin, cadmium, and zinc

Gold, silver, copper, and nickel

Table 10 Organic finishing systems for magnesium alloys

Typical finishing system for Appearance

effect

Interior service (a) Exterior service (b)

μ

Table 11 Military finishing systems for magnesium alloys

Operation Appearance Applicable specifications

•

•

•

Proc Int Magnesium Association

A Bloyce, P.H Morton, and T Bell, University of Birmingham, U.K

Materials Properties Handbook: Titanium Alloys,

Cleaning and Descaling Problems

•

•

•

•

Ti-6Al-4V alpha case 250×

•

•

Removal of Scale

Cleaning and belt grinding sequences for Ti-6Al-4V sheet

• Wet blasting:

• Dry blasting:

Effect of surface condition on etched metal surface

•

•

•

Table 1 Low-temperature salt bath and acid bath conditions for cleaning titanium alloys

Scale formation temperature

Sample

composition

°C °F

Salt bath immersion time (a) , min

Acid cleaning bath time (b) , min

Acid cleaning bath time (c) , s

Pickling Procedures following Descaling

Table 2 Corrosion of titanium in sulfuric acid pickle baths

Bath temperature Corrosion rate Sulfuric acid