Martensitic stainless damascus steel...Martensitic stainless damascus, 93x Damasteel’s martensitic...

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US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se Product information Martensitic stainless damascus, 93x Damasteel’s martensitic stainless Damascus steel is a powder based steel with the two alloys RWL 34 and PMC 27. They are both variations of the martensitic stainless steel 420 type with a minimum of 13 percent chromium content. These alloys may be considered for a wide variety of applications where one or more of the following properties are important: High hardness after hardening and tempering High corrosion resistance Easy grinding and polishing High purity and cleanliness Each alloy represents a good combination of corrosion resistance and hardenability. This combination of properties is a reason for its impressive suitability as knife material. Some examples of other applications are flatware cutlery, jewelries, and any other products where corrosion resistance and hardness are important. Grade Etch color C Si Mn Cr Mo V RWL34 Bright 1,05 0,50 0,50 14 4 0,2 PMC27 Dark 0,60 0,50 0,50 13 - - Table 1. Nominal chemical compositions in wt-% of the constituent alloys Martensitic stainless damascus steel

Transcript of Martensitic stainless damascus steel...Martensitic stainless damascus, 93x Damasteel’s martensitic...

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Damasteel’s martensitic stainless Damascus steel is a powder based steel with the two alloys RWL 34

and PMC 27. They are both variations of the martensitic stainless steel 420 type with a minimum of 13

percent chromium content. These alloys may be considered for a wide variety of applications where

one or more of the following properties are important:

• High hardness after hardening and tempering

• High corrosion resistance

• Easy grinding and polishing

• High purity and cleanliness

Each alloy represents a good combination of corrosion resistance and hardenability. This combination

of properties is a reason for its impressive suitability as knife material.

Some examples of other applications are flatware cutlery, jewelries, and any other products where

corrosion resistance and hardness are important.

Grade Etch color C Si Mn Cr Mo V

RWL34 Bright 1,05 0,50 0,50 14 4 0,2

PMC27 Dark 0,60 0,50 0,50 13 - -

Table 1. Nominal chemical compositions in wt-% of the constituent alloys

Martensitic stainless damascus steel

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Mechanical and physical properties

Mechanical and physical properties of annealed 93x (bar and plate), minimum values at 20°C.

Yield strength, Rp 0,2 270 MPa Young’s modulus 200 GPa

Tensile strength, Rm <700 MPa Poisson’s ratio 0,3 -

Elongation, A5 45 % Thermal conductivity 15 W/m·K

Hardness <700 HV Heat capacity 460 J/kg·K

Density 7,8 kg/dm3 Electrical resistivity 0,73 µ·Ω·m

Table 2. Mechanical and physical properties of Damasteel martensitic stainless steel (93x) in annealed condition.

Corrosion resistance

The martensitic stainless steels have a moderate to good corrosion resistance and are therefore

suitable for a wide range of applications. The addition of Molybdenum in RWL34 as one of the alloys

gives our damascus steel a higher corrosion resistance compared to standard martensitic stainless

steels.

Hot working

Hot working temperature 1050-1160 °C (1920-2120 F)

Compared to low alloyed steels, martensitic stainless steel has higher, almost doubled deformation

resistance. Hand forging can therefore only be performed on relatively small dimensions. Melting

starts at 1220°C (2230 F) which means that the material is very sensitive to overheating, see fig. 1. A

good control of the heating temperature is needed. An electric or gas fired furnace is recommended.

Long soaking times above 850°C (1560 F) leads to decarburization and scale formation.

After the hot working process, a slow cooling is recommended due to the risk of cracks when the

material phase transforms to martensite at around 200 °C (390 F). Usage of vermiculite or other heat

insulating material is recommended.

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Figure 1. Overheated material with its characteristic cracks from the edges towards the center of the piece.

Heat treatment

Because of the risk of cracking; no grinding, cutting or machining should be done after hot working

until the material is annealed. The recommendation is to have the material fully transformation

annealed which means one hour at 900 °C (1650 F), then cool to 750 °C (1380 F) during one hour and

finally hold at 750 °C for four hours. All martensitic material supplied from Damasteel is soft annealed

to 230 – 280 HV (20 – 28 HRC).

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Hardening

For knife applications the following heat treatments can be recommended for a 3,2 mm thick piece.

Hardening

temperature (A)

Tempering

temperature (T)

Tempering

time

Hardness

RWL34

Hardness

PMC27

I 1050 °C

1920 F

220 °C

430 F

2 h 59 HRC 53 HRC

II 1050 °C

1920 F

175 °C

345 F

2 h 62 HRC 54 HRC

III 1080 °C

1980 F

220 °C

430 F

2 h 58 HRC 56 HRC

IV 1050 °C

1920 F

175 °C

345 F

2 h 63 HRC 58 HRC

V 1100 °C

2010 F

175 °C

345 F

2 h 63 HRC 60 HRC

Table 3. Hardening and tempering suggestions for a 3,2 mm thick piece with corresponding hardnesses of the alloys

The suggested heat treatment processes IV and V includes deep freezing (DF) at -80°C (-110 F).

To ensure that best corrosion properties are achieved we recommend a low tempering temperature.

The following time temperature curve can act as a guide, see fig. 2 on the next page.

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Figure 2: Schematic hardening and tempering curve

A Austenitizing. Holding time 8 min on a 3,2 mm thick piece. Increase or decrease that holding

time with one minute per half mm of thickness

Q Rapid cooling to room temperature. We suggest quenching in oil and that the piece reaches

room temperature within two min. Apply some pressure on the piece if cooling in air so it will

not bend due to uneven cooling

DF Deep freezing is not necessary but completes the martensite transformation and increases

hardness. Hold for approx. one and a half hour

T Tempering. Holding time two hours

Cold working

Martensitic stainless steel does not cold work as easily as the conventional austenitic stainless steels

but can be formed and fabricated by a full range of cold working operations. The ductility is good and

any cold working process will increase the strength and the hardness of the material.

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Welding

When cooling martensitic stainless steel after any hot process the martensitic phase transformation

occur at around 200 °C and can lead to cracking. This can be avoided either by preheating the piece or

do a post-weld heat treatment.

Our damascus can be welded by a full range of conventional welding methods.

Machining

As with the conventional austenitic stainless steels, the martensitic steels have some specific

machinability properties. The martensitic stainless steels are generally easier to machine than other

stainless steel grades. The machining characteristics for our martensitic stainless damascus are

• Low tensile strength but a strong work hardening

• Tendencies for buildup of material on the tool edge

• Tough and stringy chips can be prevented by using chip curler tools

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Grinding and polishing

Normal grinding and polishing procedures for austenitic stainless can be used also for the martensitic

stainless steel.

Grinding wheel recommendation:

Silicon Carbide, 46 grit, soft, open density, ceramic bonded. (C46J6V)

• Speed: 35 m/sec

• Feed: 0.01-0.05 mm/stroke

Speed of the work piece may be 1/60 of the grinding speed.

Hardening and etching process

1. Grind the piece into desired shape with grit 60 and 120

2. Harden by following the instruction on the previous page

3. Polish with a fine trundle with wax

4. Follow the etching instruction on the next page

5. Clean the piece in water

6. Grind the final edge if you are making a knife

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Etching

To make the pattern in our steel visible, an etching has to be made. Depending on desired result,

different acids and acids mixtures can be used. In the table below are a few suggestions.

1. Polish the piece and degrease it carefully. Finish with oil free acetone

2. Mix the etching acid in below ratios and remember to always pour the acid into the water

Acid Chem.

comp.

Blend

(%)

Time

(min)

Color RWL34 Color PMC27

1 Hydrochloric acid 37 % HCl 100 5 Bright grey Light grey

2 Sulfuric acid 30 % H2SO4 100 5 Light grey Grey

3 Hydrochloric acid 37 %

Vinegar / Ferro chloride 30 %

HCl

-/FeCl3

100

50/50

30

30

Light grey/

bright grey

Dark grey

Table 4. Etching suggestions with corresponding colors and relief of the different alloys

Beware of noxious fumes. Acids must be handled with great care.

Formula number three is a high-contrast etching which requires two steps. First, etch in HCl for 30

minutes and directly afterwards etch in the mix of FeCl3 and Vinegar for another 30 minutes.

3. Put the piece in the mix and leave it in for the time you choose. The suggested times on the

previous page gave proper results

4. Neutralize the piece by, for example, dip it into water with bicarbonate

5. Clean in water

6. Formula number three requires a light buff with a high-grit grinding belt

7. If needed, carefully polish the surface so the tops will be shiny. If you polish too much the

pattern will not show and you will have to start over from the beginning

8. Clean the piece from polish paste residues

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

9. If you are making a knife, grind the final knife edge at this point

Etching is done to reveal the pattern on the finished piece. The best conditions for etching are good

polished surfaces which are carefully degreased. The work piece is preferably dipped into the etching

acid. After etching the piece must be thoroughly cleaned in water. A final cleaning with brush and soap

eliminates the risk for acid dwell.

Patterns

Our standard patterns in martensitic stainless Damascus steel are listed below. In every picture there

is a bevel from half the width and down

HuginTM

Suitable for smaller pieces and knives Odin HeimTM

An allround pattern suitable for any application

VinlandTM

Our random pattern. Beautiful on kitchen knives, medium sized

knives and jewelries

Dense TwistTM

Twisted material available in both flat and round condition.

Suitable for any application

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Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Rose The traditional rose pattern gives a neat effect when grinding

a phase. Suitable for medium and smaller sized knives and

applications

Odins EyeTM

A sparse variant of Hugin and suitable for medium and

larger sized knives and applications

Grosserosen A traditional pattern that looks really nice on medium sized

and larger pieces

HakkapellaTM The symmetry in our Hakkapella pattern looks stunning on a

small to medium sized knife and similar applications

HeimskringlaTM

Our Bluetounge pattern twisted. This pattern benefits

from a large bevel and looks good in any size

Ladder All around pattern that looks good in most conditions

and especially on medium sized pieces

MuninTM

Smaller variant of ladder and thus looks great on smaller pieces.

Björkmans TwistTM

A random, twisted pattern that looks good on most sizes

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

ThorTM

Our 20th year anniversary pattern. Recommended for medium

to small pieces with small bevel

GysingeTM

Suitable for small to medium sized pieces. The pattern is surface

intense and the effect will be strongest with a small bevel

US: Damasteel Inc., 275 Joliet St., Suite 350, Dyer, IN 46311 | Office US 219-864-8915 | [email protected] | www.damasteel.com

Sweden: Stallgatan 9, SE-815 76 Söderfors, Sweden | Office +46 293 306 00 | [email protected] | www.damasteel.se

Product information Martensitic stainless damascus, 93x

Products and dimensions Damasteel has a standard product program that can be found on our website www.damasteel.com.

We make martensitic damascus steel in following formats

Plate

Sheet

Strip

Bar

Rod

Billet

Even if it comes to creating customized patterns on our damascus products or if you like dimensions

outside our standard range either on damascus, RWL34 or Nitrobe 77 – do not hesitate to contact us

at [email protected] or +46 293 30600

Information given in this datasheet may be subject to alterations without notice. Care has been

taken to ensure that the contents of this publication are accurate but Damasteel and its affiliated

companies do not accept responsibility for errors or for information which is found to be misleading.

Suggestions for or descriptions of the end use or application of products or methods of working are

for information only and Damasteel and its affiliated companies accept no liability in respect thereof.

Before using products supplied or manufactured by the company the customer should satisfy

themselves of their suitability.