LAPPING PLATES
PR Hoffman offers high-quality lapping plates for all of its double-sided machines. PR Hoffman uses high quality castings exclusively from the most technologically advanced foundries. Detailed Metallurgical Certifications can be supplied with each set of plates detailing the physical and chemical properties of the plates along with a photo of the microstructure of the cast metal. A variety of metallurgies along with optional hardening and tempering services are available.
MACHINING
- Plain, smooth, flat cast iron lap surfaces are available complete with mounting and slurry holes.
- Grooved and radial ground (OD & ID) lap plates are available complete with mounting and slurry holes. PR Hoffman offers a variety of standard groove configurations as well as customized configurations.
- Resurfacing is offered by PR Hoffman. When plate grooves have reached the end of their useful life, the grooves can be machined off and the plate can be ground flat and regrooved. This is recommended only with thick gray iron plates.
METALLURGY
- Gray Iron - Cast iron with the carbon present in the form of flake graphite. The flake graphite provides gray iron with many unique properties including superior wear resisting characteristics.
Typical Gray Iron showing type IV flake graphite structure. (100x)- Ductile Iron - Cast iron containing graphite in a spheroidal form. Ductile iron is also known as nodular iron. Ductile iron can be supplied with a primarily ferritic or a ferritic and pearlitic matrix. Martensitic ductile iron is also available. This type of iron is obtained by using special heat treat and quenching techniques that cause an acicular (needle-like) microstructure to form providing increased hardness and wear resisting characteristics.
Typical Ductile Iron showing spheroidal graphite structure.(Martensite Matrix 100x)Contact PR Hoffman for more detailed information on designing a lap plate specifically for your process requirements.
PR HOFFMAN LAP PLATE MATERIAL SPECIFICATIONS |
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Class 30 |
Class 40 |
|
Class 40 Martensite |
|
(-2) |
(-1) |
|
(-8) |
|
Microstructure |
Pearlitic |
Pearlitic |
|
Martensite |
Hardness (BHN): |
163-207 |
179-229 |
|
200-240 |
Chemical Properties %: |
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Carbon |
2.95-3.40 |
2.95-3.40 |
|
2.95-3.40 |
Silicon |
1.50-2.20 |
1.50-2.20 |
|
1.50-2.20 |
Phosphorus |
.75 MAX |
.75 MAX |
|
.75 MAX |
Sulfur |
.15 MAX |
.15 MAX |
|
.15 MAX |
Manganese |
.50-.95 |
.50-.95 |
|
.50-.95 |
Copper |
1.50 MAX |
1.5 MAX |
|
1.5 MAX |
Chrome |
|
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Molybdenum |
|
|||
Graphite |
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Size/Type: |
IV A4 (ASTM A247) |
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Class |
Class |
Class |
Class |
|
60-40-18 |
60-40-18A |
60-40-18E |
60-40-18M |
|
(-3) |
(-4) |
(-5) |
(-7) |
|
Microstructure |
Ferrite 95% |
Ferrite 98% |
Ferrite 98% |
Martensite |
Pearlite Bal. |
Pearliste Bal. |
Pearlite Bal. |
||
Hardness (BHN): |
143-200 |
143-200 |
143-200 |
200-240 |
Chemical Properties %: |
||||
Carbon |
3.20-3.75 |
3.20-3.75 |
3.20-3.75 |
3.20-3.75 |
Silicon |
2.20-2.75 |
2.20-2.75 |
2.20-2.75 |
2.20-2.75 |
Phosphorus |
.08 MAX |
.08 MAX |
.08 MAX |
.08 MAX |
Sulfur |
.020 MAX |
.020 MAX |
.020 MAX |
.020 MAX |
Manganese |
.02-.10 |
.02-.10 |
.01-.10 |
.02-.10 |
Graphite: Spheroidal |
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Size: (microns) |
20-60 |
20-60 |
10-40 |
10-40 |
Count: (pieces/square mm) |
100-180 |
100-180 |
>180 |
>180 |
1517 Commerce Ave., Carlisle, PA 17015
Phone: +1 (717) 243-9900 Fax: +1 (717) 243-4542
Email: prhoff@prhoffman.com
