pferd praxis for s.steel

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PFERD Toolsfor Use on Stainless Steel

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RAX

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Information provided byAugust Rggeberg Marienheide

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Importance of stainless steels

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Definition of stainless steels

"Stainless steel" is a collective term coveringover 120 different steel grades which share thefollowing properties:

They are alloyed with at least 10.5% chromi-um.

They are corrosion-resistant without any pro-

tective coating, forming an invisible surfacepassivation layer in the presence of oxygen.

1. The thermal conductivity of austenitic steelsis lower to that of other steels (and moststainless steels are of the austenitic type). Asa result, the heat generated by the rotatingtool is not easily dissipated via the workpieceor the chips.

2. Cutting speeds should be kept lower thanwith other steels, regardless of the machin-ing process used. The tool should not beapplied with excess pressure. Local overheat-ing may cause discoloration or distortion ofthe material, and thermal overloading of thetools would be a likely result.

3. Abrasives designed for use on stainless steelsmust contain no elementary iron, whichmight form corrosive deposits in the work-piece. Similarly, to avoid such "extraneous"rust, a tool previously used on non-stainlesssteel should never be used on stainlessgrades.

4. Chip particles from the workpiece ("sparks")may be transformed into non-stainless steelat the high temperatures developed duringmachining. Unless such particles are carefullyremoved, they too will cause extraneous ruston the workpiece surface.

Thorough chemical and/or mechanical cleaning(by etching, pickling, polishing, etc.) is there-fore indispensable to protect stainless steel

from extraneous surface corrosion. As long assuch cleaning is carefully performed and theworkpieces are kept away from non-stainlessgrades, the formation of extraneous rust onstainless steel is virtually impossible.

Importance of stainless steels

In the modern world, stainless steels are findingtheir way into an increasing number of applica-tions. Their outstanding properties, e.g.,

high resistance

toughness

have given rise to a broad variety of uses.

In addition, new grades of these materials arebeing developed continuously for specificneeds.

Today, stainless steels have become indispens-able in a broad range of industries and applica-tions including

chemical and petrochemical equipment.

foodstuff processing vessels and machinery.

process technology.

pulp and paper processing.

architecture (building fronts, handrails).

power plant engineering.

pump and turbine manufacturing.

shipbuilding (piping, containers). structural and mechanical engineering.

The particular characteristics of stainless steelsimpose specific requirements on the machiningand finishing tools used. Thus, most austeniticsteels are more difficult to machine than theirunalloyed counterparts due to their stickiness,edge build-up tendencies, and strain hardeningbehavior. On the other hand, the eco-friendli-ness of stainless steels - as expressed in theirdurability, corrosion resistance even whenuncoated, and recyclability - is a factor that hascontributed not least significantly to their evermore widespread use.

The PFERD tool range for use on stain-less steels

PFERD offers an extensive range of tools meet-ing the specific requirements of the stainlesssteel processor. Many of these tools were pur-pose-designed for this application; all havebeen found to give good results in everydaypractice.

In addition, PFERD provides free application-related advice on all machining issues involvingstainless steels - without any obligation on yourpart. Our experienced field staff and technicalcustomer service engineers will be glad to be ofhelp.

So why not give us a call?

All of these tools are free of elementaryiron, sulfur, or chlorine.

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Machining Tasks and Suitable Tools

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Stationary cutting

Stationary machines are employed, e.g., forcutting solid material, billets, pipes, and sec-tional products.

This abrasive cutting technique is often used involume production environments.

Suitable PFERD tools:

Abrasive cut-off wheels up to 1250 mm dia.

Refer to page 5.

Freehand cutting

Used on sheet metal, sectional products, pipes,and solid material.

Suitable PFERD tools:Abrasive cut-off wheels in the 30 - 300 mmdia. range

Refer to page 5.

Geometry modification on medium-to-large workpieces

For dressing surface weld joints, deburringedges, rounding off corners, etc.

Suitable PFERD tools: Reinforced grinding wheels up to

230 mm dia.

POLIFAN flap discs

Fiber discs

COMBIDISC abrasive tools

Flap wheels

Refer to page 6.

Geometry adjustments on smallerworkpieces

This includes dressing and finishing of weldjoints in corner or angle areas, edge deburring,beveling or rounding work, and removing flashfrom slots and grooves.

Suitable PFERD tools:

Files

Tungsten carbide burrs

Mounted points

POLICAP tools

POLIROLL tools

POLICO tools

Abrasive spiral bands

Ring wheels

Overlap slotted disks

COMBIDISC tools

ATADISC tools

Refer to pages 8 - 11.

Surface texturing and cleaning

Wherever surfaces are to be pre-ground, pol-ished, matt or satin-finished, marbled, orbrushed. Weld cleaning is another importantapplication.

Suitable PFERD tools:

Fan grinders, flap wheels

COMBIDISC tools

ATADISC tools

Self-adhesive grinding disks

POLINOX mounted points, ring wheels, starpads

POLINOX foamed ring wheels

POLIVLIES grinding wheels and discs

POLICLEAN tools

Marbling tools

Poliflex fine grinding wheels

Brushing tools

Abrasive cloth rolls

POLIVLIES hand pads

POLICLEAN tools

Refer to pages 11 - 14.

Mechanical surface polishing

Surfaces can be mechanically polished to ahigh luster. This is achieved with the aid of arotating basic tool to which a polishing paste isapplied.

Suitable PFERD tools:

Cloth rings, in conjunction with polishingpaste (bars)

Non-woven abrasives, in conjunction withpolishing paste bars, diamond polishingpaste or grinding compound

Refer to page 15.

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Superior Finishes - from Coarse to Mirror-Polished

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Stage 4

This very fine surface can beproduced using the tools listedat right, starting out from a Stage 3 finish:

Stage 3

This fine surface can be producedusing the tools listed at right, startingout from a Stage 2 finish:

Stage 2

This rough surface can be obtained with thetools listed at right, starting out from a Stage1 finish:

Stage 1

This very rough surface can be produced withthe tools listed at right:

This satin-finish surface can be produced withthe tools listed below:

Tools for Stage 1

Depressed-center grinding wheels

POLIFAN flap discs

Fiber discs

Abrasive spiral bands

Fan grinders

Flap wheels

COMBIDISC abrasive discs

COMBIDISC Mini-POLIFAN discs

Mounted points ADW/AWN/AW/AN,hardness grades I/H/L/M/N

Satin-finishing tools

POLINOX points, wheels and rolls,PNL/PNR/PNZ/PNL types (aluminium oxide orSiC)

POLINOX foamed ring wheels PNK

Power Brushes

Marbling tools

Poliflex marbling tools

Marbling tools carrying non-woven abrasivediscs

Matt-finishing tools

POLINOX points, wheels and rolls

POLINOX foamed ring wheels PNK

Poliflex

mounted points, PUR bond

Cleaning tools

POLIVLIES abrasive spiral bands

INOX brushes

SiC brushes POLINOX points, wheels and rolls

COMBIDISC non-woven abrasive discs(hard type)

POLICLEAN non-woven abrasive tools

Rough to very fine surface grinding Surface texturing steps followingStage 3 surface preparation

This marbled surface can be produced withthe tools listed below:

This matt-finished surface can be producedwith the tools listed below:

This cleaned surface can be obtained with thetools listed below:

Tools for Stage 2

POLIFAN flap discs

Fan grinders

Flap wheels

COMBIDISC abrasive discs

COMBIDISC Mini-POLIFAN discs

COMBIDISC POLIVLIES discs (hard type)

POLIVLIES discs, PV type

POLIVLIES hook-and-loop discs

POLICLEAN tools

Mounted points (ADW bond type)

Tools for Stage 3

Poliflex fine grinding points with GH, GHR,PUR and TX bond

Poliflex fine grinding wheels with GR andPUR bond

Poliflex blocks

POLIVLIES abrasive spiral bands, hand pads

INOX brushes / SiC brushes

Fan grinders

Flap wheels

COMBIDISC abrasive discs

COMBIDISC non-woven abrasive discs (soft)

POLINOX points PNL, PNR, PNG, PNZ POLINOX ring wheels / rolls

Tools for Stage 4

COMBIDISC non-woven abrasive discs (soft)

COMBIDISC felt discs with grindingcompound / diamond polishing paste

Cloth rings, used with bars of polishing paste

Felt points with and without metal insert, in

conjunction with grinding compound or dia-mond polishing paste

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Abrasive Cut-Off Wheels

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Abrasive cut-off wheels for stationarymachines

The use of abrasive cut-off wheels on station-ary machines has evo