hitachi forged high speed steel · pdf filehitachi forged high speed steel rolls ... forging...

HITACHI

FORGED HIGH SPEED

STEEL ROLLS

May 2013

Hitachi Power Solutions Co., Ltd.

CX-12-029R2

2000Ton Forging Press & 40MT Manipulator

© Hitachi Power Solutions Co., Ltd. 2013 All right reserved.

●Hitachi Forged HSS rolls

Hitachi has developed HSS rolls for sendzimir-mill from the 1950s, and has supplied many

small HSS rolls to the sendzimir-mill customers. After that, from the 1980s, proprietary was

carried out and the ESR equipment "rotational ESR bimetallic method " which has a special

structure was succeeded in development by compounding the HSS roll for tandem-mill, with

difficult manufacture by solid body.

According to the expansion of hybrid car, etc., Hitachi has supplied HSS rolls (Hitachi

symbol, E61) and Super HSS rolls (Hitachi symbol, E70) to the hard materials rolling

tandem-mill, such as silicon steel, now.

● Hitachi Forged Semi-HSS rolls

Hitachi has introduced Advanced ESR equipment, featured (1) fully coaxial high current

feeding system, (2) swing control system, in 2008. This ESR method can supply a quality

ESR ingot with fine dendrite micro structure. By application of this ESR method, the grinding

control for Semi-HSS roll is greatly improved Advanced ESR is applied to manufacturing

the rolls for the rolling mill of high-strength steel sheet and hard tin plate, and Hitachi

supplies Semi-HSS roll (Hitachi symbol, FH-20) of the solid body which reconciled wear

resistance and grinding control.

Year

Material Transition and Manufacturing Development

ESR(20ton) Ladle Refining

Low Frequency Induction Hardening

Sub Zero Treatment

Automatic Ultrasonic Detection

ESR(10ton)

Rotational ESR

Bimetallic Method

Ultrasonic Hardness

Penetration Measurement

High Speed Steel

FH-15 (5%Cr)

FH-11 (3%Cr)

FH-8 (2%Cr)

CNC Lath Machine

Power-up

CNC Carving Machine

Wear Resistance

’75 ’80 ’85 ’90 ’70 ’95 ’00 ’05 ‘10

Advanced

ESR(20ton) 6000ton Forging Press

2000ton Forging Press

Wear Resistance

and

Grinding Control

Development of Hitachi Forged HSS Rolls

1


Finished Rolls

Spheroidizing

Automatic Ultrasonic Flaw Detection

Thermal Refining

EF-Melting + LF-LD

Forging

Spheroidizing

Machining

Automatic Ultrasonic

Flaw Detection

Core

Rotational ESR

Bimetallic Method

Pipe-Shaped

Electrode

Rough Machining

Finish Machining

Heat Treatment

Final Inspection

Packing

Manufacturing Process of HSS Rolls

Forging

2


Rotational ESR Bimetallic Method

Down

Up

Pipe-Shaped

Electrode

Core

Water-Cooled

Rotational Crucible

Molten Slag

Molten Pool

Rotational Plate Carbon Brush

Characteristics

Wide range combination of shell and core

High purity and Fine and Sound structure

High strength boundary layer between shell

and core

High performance High-Speed-Steel Roll

Core Pipe-Shaped

Electrode

Synchronously Rotation

Hitachi HSS Rolls

Outer Layer

Set up Melting Set off

A Cross- sectional

Macrostructure of

Composite Ingot

3


400μm

Advanced ESR Method

Characteristics

Feeding System ； Fully Coaxial High Current Feeding System

Control System ； Slag Pool Resistance Swing Control

High quality ESR Ingot with ultra fine dendrite structure

Hitachi Semi-HSS Rolls

Ram Drive system

XY Adjustment

Load cell System

Sliding Contact

Exhaust & Atmospheric Protection Hood

Gantry

Slag Feeder

Coaxial Bus bar

Stationary Mold Crucible

Base Plate

Ingot

Molten Slag

Forged Electrode

Stub

Power Supply

400μm Conventional ESR Advanced ESR

Dendrite arm space by advanced ESR is a half of conventional ESR. (Compared to our company’s products)

20mm depth from roll surface

20mm depth from roll surface

4

Electrode Ram

Molten Pool


CB60M100VGP

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Ro

ug

hn

ess (

Ra)

E61 E70

GC320GmB

5SG60/80(H12VSK-1)

CX60/80(E+/F+/E+12V101P)

5SG46(H12VSG1P)

CX46(E+/F+/E+12V101P)

CB80M125VN1E

CB60M100VN1E

CB325P60Bw4

Hitachi Symbol

Recommendation of Grinding Wheel

Specification for HSS Rolls

5


HITACHI FORGED ROLL MATERIALS

Actual performance

0

0.5

1.0

1.5

5％Cr FH-20

Wear Resistance

We

ar

Am

ou

nt

(mm

dia

.)

Roll

Symbol

Wear profile of strip edge contacted

portion

FH-15

(5%Cr)

FH-20

FH-20 Semi-High Speed Steel Roll

Test piece

Φ40×8

Mild steel

Φ40×8

Slip ratio: 30％

5％Coolant

Test Method

Wear amount:

1/6 Strip edge Strip

0 Strip edge Strip

Actual rolling performance

6


HITACHI FORGED ROLL MATERIALS

Hi-NC roll has primary carbide in the matrix, it makes the wear resistance

much higher than usual rolls.

Especially E61 and E70 are high speed steel type material which can be

tempered over 500 ℃.

Table 1 shows the characteristics of Hi-NC roll.

Table1. Characteristics of Hi-NC roll

・Wear amount after 500ton hard material rolling ----------- Fig.1

・Example of surface roughness drop ----------- Fig.2

0

10

5

5%Cr

Forged roll

Hi-NC

(E61)

Wear

am

ou

nt (m

m d

ia.)

200

0

40

Su

rfa

ce

rou

gh

ne

ss d

rop

ratio

(%

)

400 600 800 0 80

Rolled tonnage (ton)

Hi-NC roll

(E61)

5%Cr (Forged roll)

Fig.1 Wear amount after 500ton hard material rolling Fig.2 Example of surface roughness drop

Characteristics of High Speed Steel Roll

Actual performance

Material Classification Primary carbide Characteristics Rolling

FH-20 Special Material M7C3

Wear resistance

(Dull keeping)

Mild

steel

E61 High speed steel MC, M2C, M6C Wear resistance

Abrasion resistance

Hard

material

E70 Super High

speed steel MC, M2C, M6C

Wear resistance

Abrasion resistance

Hard

material

E61,E70 (Hi-NC) High Speed Steel Roll

7


hitachi forged high speed steel · pdf filehitachi forged high speed steel rolls ... forging...

Documents