Straightening Rolls by Bowers & Jones

734.0

22.5⁰ 22.5⁰

90.0

⁰

+0.

358

0.0

+0.

1

90.0⁰

90.0

C

Rolls • Design + Manufacture

Rolls for Straightening Plants

Bowers & Jones design and manufacture rolls for cold straightening of long products such as:

• Black and Bright Bar

• Tubes and Pipes

• Sections and Rails

These highly stressed rolls must offer a high hardness and wear resistance with the lowest possible tendency to pick up. Rolls made from our cold work tool steels are most suitable for these applications.

Due to the very high pressure loads occurring during the straightening of round bar material, the journals of the rolls are highly stressed. In order to improve the resistance to breakage, two alternative hardening processes are available at Bowers & Jones:

• Through hardening of the rolls with the journals tempered back

• Surface hardening of pre-heated rolls (depth of hardness approx. 10-25mm)

For some applications, composite rolls are offered as a twopart design: the working part of the roll is a shell made fromZESEK or ZESEK EXTRA fi tted onto a shaft made fromtough engineering steel. The choice of the best suitable optiondepends on customers’ requirements.

A combination of ZESEK materials and our specifi c heat treatment processes gives Bowers & Jones rolls a much better stability compared to cast materials. Customers then benefi t from a better performance and much lower service life costs.

Our machining range allows us to manufacture extra-large rolls up to 1350mm diameter roll body and up to 3000mm length shafts, up to a combined weight of 8 tonnes.

Our technical staff will be happy to give you further advice on design and material selection.

NominalAnalysis C

1.551.55

Si

0.250.30

Mn

0.300.40

Cr

11.7511.50

Mo

0.700.70

V

1.000.80 %

Characteristics

Ledeburitic 12% Cr steel with excellent toughness, very high wear resistance, and cutting edge retention. Using a hardening temperature of 1060-1080ºC (secondary hardening) and double tempering, the steel can be nitrided.

Typical ApplicationsShear blades, tube mill rolls, rolls for cold rolled sections, stretch reducing mill rolls (specially treated), cold straightening rolls, polishing rolls.

Heat treatment

Annealing 820-850ºC

Annealing hardness max, 255HB

Stress relieving 650ºC

Hardening 1000-1040ºC/air, oil or hot bath 500-550ºC

Secondary hardening 1060-1080ºC/air, oil or hot bath 500-550ºC

Tempering see tempering graph; at least twice after secondary hardening

ZESEKZESEK EXTRA

Hardening depth for 58 HRc

mat

erial

num

ber

Component diameter in mm

Dependency of Hardening Depth on Component Diameter

Har

dnes

s pe

netr

atio

n in

mm

1.25

50

1.27

671.

2842

1.20

80

1.24

361.

2601

1.23

79

90

80

70

60

50

40

30

20

10

080 100 120 140 160 180 2006040200

Superior Material Properties

ZESEK, W. Nr. 1.2379 (~AISI D2) is a forged ledeburitic high carbon high chrome cold work tool steel alloyed with Mo and V. Compared to cast D2, ZESEK has no porosity or other casting defects which increases its crack resistance.

ZESEK EXTRA a further development of the well-known tool steel ZESEK with very similar chemical composition but with a more homogeneous microstructure.

Fig1. Conventional W.Nr. 1.2379 (AISI D2) with typical lines of primary carbides

Fig2. ZESEK EXTRA with better distributed primary carbides

Due to the fi ne and more homogenous structure (see Fig. 2) the chipping resistance has been enhanced for a longer roll life. Because of the better distribution of primary carbides the abrasive wear resistance is slightly better compared to conventional W. Nr. 1.2379. By using Bowers & Jones’s special heat treatment the steel can also be used in selected hot rolling applications.

®Roll TypeRecommended materials Märker

Material No.AISI (ASTM)

Usual hardness HRc

Tensile strength

Rm=N/mm2

Hardening process SH = Surface hardening, TH = Through hardening

Straightening rolls for Bars ZESEK 1.2379 D2 56 - 62 SH + TH(one or two part design) SRSE 1.2714 L6 56 - 59 SH

ZESEK EXTRA - - 56 - 62 SH + THStraightening rolls for Tubes ZESEK 1.2379 D2 56 - 62 SH + TH(one or two part design) SRSE 1.2714 L6 56 - 59 SH

ZESEK EXTRA - - 56 - 62 SH + THShafts for two part rolls SRSE 1.2714 L6 900 - 1100

30CrNiMo8 1.6580 - 800 - 120034CrNiMo6 1.6582 - 800 - 120040CrNiMo6 1.6565 4340 800 - 120042CrMo4 1.7225 4140 750 - 950

Straightening rolls for Rails ZESEK 1.2379 D2 58 - 60 THStraightening rolls for Sections ZESEK 1.2379 D2 58 - 60 TH

Bowers & Jones Limited

Head Offi ceHilton Cross Business ParkFeatherstoneWolverhamptonWV10 7QZUnited Kingdom

Phone: +44 1902 732110

E-mail: sales@bowersjones.co.uk

www.bowersjones.co.uk

Vat №. GB-897695840

Registered in England

Company №. 546897

Bowers & Jones Limited has made every attempt to ensure the accuracy and reliability of the information provided on this brochure. However, the information is provided “as is” without warranty of any kind. Bowers & Jones Limited does not accept any responsibility or liability for the accuracy, content, completeness, legality, or reliability of the information contained on this brochure.

Rolls • Design + Manufacture