Fabrication of Zirconium Alloy Cladding Tubes and

Other Fuel Assembly Components

for Water-Cooled Reactors
Workshop on Modeling and Quality Control for
Advanced and Innovative Fuel Technologies
Lecture given
at International Centre of Theoretical Physics
in Trieste on November 22, 2005

Hans G. Weidinger, Nrnberg/Germany

CONTENT

Zr-Materials
Zr Basics
Zr-Materials for LWRs
Fabrication:
Conversion of Zr-Sand to Zr-Chloride/-Fluoride
Hf/Zr Separation
Reduction of ZrCl4/ ZrF4
Alloying Melting
Hot Deformation
Beta Quenching
Cold Deformation

BASICS OF ZIRCONIUM
Basic physical/chemical properties,
Crystallographic Structure and Texture
Chemical Composition of Zr and Standard
Zr-Alloys
Phases, Precipitates
Basic Characteristics of Improved and
Advanced Zr-Alloys

PHYSICAL PROPERTIES

Atomic Number
Atomic Weight
Density
Elasticity Module
Melting Point
Boiling Point
Allotropic Modification
Linear Thermical Expansion Coefficient
Specific Heat
Specific Electrical Resistance
Macroscopic Cross-Section
for Thermical Neutrons

40
91,22
6,5 g/cm2
96.000 MPa
1875C
3577C
865C
5,8x10-6/C
0,067 cal /g/C
40
/cm
0,0079 cm-1

Acc. J.H. Schemel ASTM Manual on Zirconium and Hafnium, ASTM STP 639 (1977) p.4

HEXAGONAL ZR-CRYSTAL

Twin
Layer
(1022)

A-AXIS

Twin
Layer
(1012)

C-AXIS

Pyramid
Gliding
Layer
(1011)
Prism
Gliding
Layer
(1010)

CRYSTAL TEXTURE IN
ZR ALLOY CLADDING TUBES

Circumferential
Texture of basal poles

Random Texture
of basal poles

Radial Texture
of basal poles
Unit cell
hexagonal
close-packed
structure of
Zircaloy

30

30

Usual Texture
of basal poles
in cladding tube

By SSM "Zirconium Alloy Fuel Clad Tubing-Engineering Guide 5th Edition Press Craft, Pasco/WA,USA(1989)

Commercial Zr-Materials for LWRs

Material

Application

Zircaloy-2

BWR FR cladding,
with internal liner (ZrFe, ZrSn, Triclad)

Zircaloy-4

BWR fuel structure (spacers, channels)

PWR FR cladding & FA structure (classic)

M5

PWR FR cladding & FA structure (advanced)

ELS-Duplex

PWR FR cladding

ZIRLOTM

PWR FR cladding & FA structure (advanced)

E110

WWER FR cladding
WWER structure

Zircaloy Composition
AlloyElement

Zircaloy-2

Zircaloy-4

Tin
Iron
Chromium
Nickel

1.20 - 1.70
0.07 - 0.20
0.05 - 0.15
0.03 - 0.08

1.20 - 1.70
0.18 - 0.24
0.07 - 0.13
-

Fe+Cr+Ni
Fe+Cr

0.18 - 0.38

0.28 - 0.37

Oxygen
Silicon

0.09 - 0.16
0.005-0.012

0.09 - 0.1
0.005-0.012

ADVANCED ZR ALLOYS FOR PWR

COMMERCIALLY INTRODUCED

FRAMATOME
M5:

Zr 1 Nb solid tube, with optimized chemical composition and

low temperature fabrication process, recrystallized

SIEMENS
ELS 0.8 Duplex:

OD-Liner with Zry-4 with 0.8 Sn on standard Zircaloy-4, fabrication

similar to optimized Zircaloy-4

WESTINGHOUSE
ZIRLOTM:

Zr1Nb1Sn 0.1Fe solid tube, with special heat treatments

E 110 (Zr1Nb)
Chemical Composition Zr1Nb

Element

Tolerable
wt%

Niobium

Typical
wt%

0.9 - 1.1

0.95 - 1.10

Tin
Iron

< 0.05
< 0.05

Oxygen
Nitrogen
Hydrogen

< 0.1

Carbon
Silicon

< 0.02
< 0.02

0.003 - 0.007
0.004 - 0.009

Hafnium

< 0.05 (0.01)

0.03 - 0.04 ( < 0.008)

E-110 Alloy Cladding Tube Properties and Their Interrelation

With Alloy Structure Phase Condition And Impurity Content

<

0.001
0.014

0.05 - 0.07
0.003 - 0.004
< 0.006
0-0004 - 0.0007
< 0.0015

P.V. Shebaldov et.al., 12th ASTM Zr Conference,

Toronto, Canada, June 15 18, 1998

PHASES, CRYSTALLOGRAPHIC STRUCTURE,

DEFORMATION MECHANISMS OF ZIRCALOY

STRUCTURE

-phase

cubicbody-centred

C
1000

900

Temperature

800

+mixed phase

-phase

recrystallisation

500

diffusionprocesses

grain-boundarygliding

Superplasticity

diffusion
controlled
dislocation
prozesses

dynamic
recrystallisation

and
recovery

400

DEFORMATION -MECHANISMS

++

700
600

cubic/
hexagonal

hexagonal

PHASES

dislocation
gliding

therm. activated
creep
irradation
induced creep

H.G. Weidinger et al., in Ilschner: Density and Deformation under High Temerature, DGM, Oberursel, Germany (1983) pp. 137 ff.

TEMPERATURE

PHASEDIAGRAM OF THE SYSTEM Zr - Nb

IN TEMPERATURE RANGE 600 - 900C,
SECTION Nb: 0 - 14%

900
C
850

-Zr

800
750

-Zr + -Zr

700

-Zr

650
600

-Zr + -Nb
0

10

11

12

13

14

Wt - % Nb
ACC. BETHUNE AND WILLIAMS

ADVANCED CLADDING TUBES FOR BWR

COMMERCIALLY INTRODUCED
ABB

Sn Barrier

Zircaloy-2 solid tube (heat treatments LK-2 or LK-3) plus

Sn-alloyed liner on ID (0,25% Sn)

GENERAL ELECTRIC
Classical Barrier
TRICLADTM

Zircaloy-2 solid tube plus

Zr-(unalloyed) liner on ID ( 400 ppm Fe, < 600 ppm O)
Zircaloy-2 solid tube plus
Zr-(unalloyed) liner on ID ( 400 ppm Fe, < 600 ppm O) plus
2nd Zircaloy-2 liner; base tube with ex (
+
)-quenching on OD-layer

SIEMENS
Fe-Barrier

Zircaloy-2 solid tube plus

Fe-alloyed liner on ID (0,4% Fe)

ADVANCED ZR ALLOYS FOR PWR AND WWER

COMMERCIALLY PROPOSED

FRAMATOME
M4:

Zr 0.5 Sn 0.6 Fe 0.4 V solid tube, fabrication similar to optimized Zry-4,

fully recrystallized

SIEMENS
Zr1Nb

OD-Liner solid tube, partially recrystallized, with special

heat treatment

WWER (RBMK)
E-635

Zr1.2Nb1Sn 0.4 Fe solid tube with special heat treatments

FABRICATION
Basic Differences West - East
Conversion of Zr-Sand to Zr-Chloride/-Fluoride
Hf/Zr Separation
Reduction of ZrCl4/ ZrF4
Alloying Melting
Hot Deformation
Beta Quenching
Cold Deformation

Zirkon Sources
Zr material fabrication everywhere in the world starts from the mineral Zirkon which
occurs very frequently all over the world as ZrSiO2.
Western production normally uses beach sand from Australia and South Africa. For
example Framatome-ANP in France buys approximately 50% of its demand each from
both countries. And it receives it already ground to a fine powder (flour).
Zirkon from Russia the Ukraine is used for Eastern production .

Basic Fabrication Differences West East

Western Technology
There are 3 companies producing nuclear grade Zr-products:
Wah Chang and Western Zirconium in the US, and
Framatome-ANP in France
In all three companies the fabrication from the raw material Zr-sand to the alloyed metallic
ingot is based on a Zr-tetrachloride technology.
There is only one difference between production in the US and France:
the Zr/Hf separation technology.
Eastern Technology
There are 2 companies producing nuclear grade Zr-products:
Chepetsky Mechanical Plant in Russia, and
SSPE-Tsircony Plant in Ukraine
The Russian fabrication from Zr-raw material to the alloyed metallic ingot is based on a Zrtetrachloride technology.
The Ukrainean fabrication from Zr-raw material to the alloyed metallic ingot is based on a
Zr-tetrafluoride technology.

Technological Differences between

Western and Russian Production

Fabrication Steps

Western

Russian

Starting Material

Beach Sand from

Australia

Ore from open pit in

Ukraine

Hf Separation

Extractive Distillation
Liquid-Liquid Extraction

Fractional Crystallization

Reduction to Metal

Kroll Process:
Reduction by Mg

Molten Salt Electrolysis

Refinement

None

Zr-Iodide Process

Zirconium

30% Scrap +
Zr Sponge

10% Scrap + 30% Crystal

Bar + 60 % Zr-Powder

Schematic Depiction of The Loca Difference inTemperature

vs. Time History During Vacuum Annealing of Zircaloy Tubes

The processes following, from melting to final product are similar,

with differences in details

MANUFACTURING ROUTES - WESTERN TECHNOLOGY

OVERVIEW
Zirconium Sand
Zr - Hf Separation
Zr02 - Reduction
Zirconium Sponge
Scrap Recycling

Alloying - Melting
Hot Rolling

Zircaloy Ingot
2nd Hot Forging
Extrusion
Annealing
Tube Hollow
Rocking
Annealing

Multiple

Cladding Tube
Guide tube
Fuel Rod Manuf.
Structure Manuf.

1st Hot Forging

Beta-Quenching

Multiple Cold Rolling Multiple

Annealing

Billets

1st Hot Rolling

2nd Hot Rolling
Cold Rolling
Annealing

Cold Rolling
Annealing

Wires

Bars
Multiple

Sheet
Spacer Manuf.
Channel Manuf.

End Plug Manuf.

Plate Manuf.
Fuel Rod Manuf.
Fuel Assembly Manuf.

Spacer Manuf.
Fuel Rod Manuf.

ZrSiO4 + K2SiF6
Zr - Hf Separation Fractional Recrystallization

Van Arkel
Process

Zr-Powder

Jodide-Zr
10% Scrap
+ Nb Powder (& Other
Alloy Elements)

30%

Leaching, Granulating, Grinding

Carbonate- & Acid-Treatment

60%

Electrode
Preparation

1st & 2nd Melting

Scrap

+ KCl Electrolysis, ~ 800C

Reduction

Zr-Alloy
Ingot

Blending, Mixing,
Pressing to Briquets, Sintering
Vacuum Arc Melting

Machining, Surface EB-Melting

Further Processing
Source: Chepetsky Mechanical Plant, Glasov, Russia

Fabrication Sequences to Produce Zr-Alloy Material

in Glasov, Russia

Zr-Silicate

1. Thermochemical
Conversion of Zr-Ore

(+ Na-Carbonate; Fusion)

Na-Zirconate
(+ H2O + HNO3 ; Leaching)

Zr-Nitrate

2. Separation of Hafnium

Zr - Hf Separation
Zr-Nitrate
(+ HF3; Precipitation)

Zr-Tetrafluoride
(monohydrate)
(+ Ca + Nb; Reduction and Alloying)

3. Alloying, Reduction
to Metal, Melting

Zr-Raw Metal
(Electron-Beam Melting)

Zr1Nb Ingot

Fabrication Sequences to Produce Zr-Alloy Material

in the Ukraine
Source: SSPE-Tsircony Plant, Dnjeprodzerzinsk, Ukraine

Western Fabrication Steps from Raw Matrial to ZrAlloy Ingot

Conversion of Zr-Sand to Zr-Chloride
Hf/Zr Separation
Reduction of ZrCl4
Alloying Melting

Conversion of Zr Sand to Zr-Tetrachloride

Carbo-Chlorination
The first step after physical enrichment is a chemical conversion of the natural rawmaterial to Zr-tetrachloride which is performed by a carbo-chlorination (fig. 1) according
to the reaction:
ZrO2 (+SiO2 + HfO2) +2C + 2Cl2 ZrCl4 (+SiCl4 + HfCl4) + 2 CO
With selective condensation the the mixed Zr- and Hf- chloride is separated from the Sichloride, while the residual gases, particularly carbon monoxide are finally released to
the atmosphere or recycled to another chemical plant.

Conversion of Zirkon-Sand to ZrCl4 by

Carbo-Chlorination

Main
Filter

Filter
Condenser

Entering Mixture
C + ZrHf O2
Gases

Fluidized Bed for

Carbo-Chlorination
Water
Entering Cl2

Exit ZrHfCl4

Source: Framatome-ANP

24

Carbo-chlorination of Zr-SAND and Hf-Separation

Western Technologies

Source: Framatome-ANP

Hf/Zr Separation
Liquid-Liquid-Extraction
Zirconium and Hafnium have to be separated for nuclear purposes. This is performed in the US at
Wah Chang and Western Zirconium by liquid-liquid extraction.
For the liquid-liquid extraction process
The mixed ZrHf-chloride is dissolved in hydrochloric acid.
The Zr and Hf ions are complexed with ammonium-thio-cyanate to Zr(SNC)2/Hf (SNC)2.
Hf is extracted with methylisobutyl ketone (MIBK) in a counter current liquid-liquid
extraction system.
The aqueous phase, containing the Zr, is mixed with sulfuric acid to precipitate the Zr
as hydroxide with the addition of ammonium hydroxide.
After filtering the Zr-hydroxide is calcined to ZrO2.
Hf is stripped off from the MIBK with hydrochloric acid and recovered to oxide similarly as Zr.
For this separation process the carbo-chlorination has to be repeated to produce a Hf-free
ZrCl4 to be reduced to Zr-metal (see Kroll process).
With this process Hf contents of 40 50 ppm remaining in the Zr could be achieved already years
ago.

Hf Separation by Liquid-Liquid Extraction with MIBK

Zr/Hf oxy-cloride

ZrOCl2/HfOCl2

NH4SCN

Zr/Hf thio-cyanate

ZrO(SCN)2/Hf(SCN)Cl2

HSCN/MIBK

2nd cycle
aqueous phase
Zr O(SCN)2
HCl

organic phase
Hf O(SCN)2
H2SO4

Zr O Cl2
Hf < 50 ppm

Hf O (SO4)
Zr < 4,5%

H. G. Weidinger

Hf-Separation by Liquid -Liquid Extraction

Raw ZrCl4
(with Hf)
Water

ZrOCl2
HfOCl2
MIBK

Thiocyanate
SNC NH4
HfO(SNC)

SO H
4

NH OH
4

ZrOCl

Zr(OH)

CALCINATION

ZrO2
(Hf-free)
Source: CEZUS

Hf/Zr Separation
Extractive Distillation
Zirconium and Hafnium have to be separated for nuclear purposes. This is performed in France
by extractive distillation
With the extractive distillation process Hf is removed by dissolving the ZrHf-chloride in
potassium-aluminum chloride (KCl-AlCl3).
A solvent made of molten KCl-AlCl3, is circulated from the top to the bottom (<10.000 l/h).
Vapor of ZrCl4 (500C) rises in a counterflow from bottom up.
The vapor going up is progressively enriched in HfCl4.
The liquid going down progressively looses Hf-content.
The ZrCl4 is stripped, cooled and condensed in a nitrogen stream (50m3/h).
The efficiency of the distillation process has been published as 98% as compared with the liquidliquid process with 89% efficiency.
Today < 40 ppm Hf in Zr are normal commercial quality from both types of processes.

Hf-SEPARATION
BY EXTRACTIVE DISTILLATION

L. Moulin et al., ASTM STP 824 (1984) pp. 37-44

ZrCl4 Nuclear-Grade Composition Referred to Zirconium Basis

LIQUID/LIQUID
DEHAFNIATION

DEHAFNIATION EXTRACTIVE
DISTILLATION

(ppm)

(ppm)

Zn

< 120

< 120

< 100

< 100

Hf

30/80

35/60

Al

5/50

10/60

Na

< 50

< 50

Si

< 30

< 30

Ca, Fe, Ti

< 20

< 20

Cr, Cu, Mg, Mn, Mo, Ni, Pb, Sn, V

< 10

< 10

<3

<3

< 0.5

< 0.5

ELEMENT

New Process for Zirconium and Hafnium Separation

th
Moulin et.al., Zirconium in the Nuclear Industry, 6 Intl Symp.
ASTM STP 824, 1984,

Reduction of ZrCl4
Regardless which Zr/Hf separation process is used the next step in commercially
producing Zr-alloys in the West is the reduction of ZrCl4 to metallic Zr.
The basic chemical process is
ZrCl4 + 2 Mg 2MgCl2 + Zr
This process is called in honor of its inventor the Kroll process.
The already rather pure Zr-tetrachloride is reduced to metallic Zr by using metallic Mg
as reductant. The purity of the Mg is very important not to enter new impurities in the
metallic Zr.
This process ends up with a very porous Zr-metal, therefore called Zr sponge.
Large pieces of Zr sponge are crushed mechanically into smaller sizes.
Besides some few volatile elements like chlorine and magnesium, all of the impurities
present at this stage will remain with the Zr and therefore also end up in the Zr-alloy.
The most common impurities are iron, nitrogen, oxygen, and aluminum.

Kroll - Process:
Reduction of ZrCl4 by Magnesium

Hf free ZrCl

CRUSHING

Compacted ZrCl

BLENDING
KROLL-REDUCTION

ZrCl + Mg
4

Magnesium

MgCl

Zr, Mg + MgCl

INSPECTION

VACUUM DESTILLATION
Zr, Mg

Zr + Mg

Mg

ZR-SPONGE

Source: Framtome-ANP

Alloying Electrode Preparation Melting

Due to the reactivity of the metal and its high melting temperature (1.850C) an
economic production uses the vacuum arc process with a consumable electrode for
melting. This melting process is performed twice or three times depending on the
experience of the producer and on customer requirements.
The necessary first step the electrode preparation for the first melting process.
The electrode contains three different sources of material: Zr-sponge, alloying elements,
recycled material.
The recycled material today originates from in house production only. Nevertheless the
recycling process consists of a sophisticated sequence of purification and control steps.
Today the ratio is much more reduced (about 25 30 % or less).
The details of the electrode preparation vary between the various producers.
At Framatome-ANP the electrode is built with briquettes weighing 50 to 60 kg, each
briquette containing all the constituents of the load in the required proportions. These
briquettes are compressed to compacts with a hydraulic press.
The compacts then are assembled by electron beam welding to an approximately 3 ton
electrode. Under these conditions generally triple melting is applied to obtain final ingots
with about 6 tons size.

Electrode Preparation

Source: Framatome-ANP

Zircaloy Electrode after Electron-Beam Welding

Melting
Melting is performed in a vacuum arc furnace with consumable electrode and a
water cooled copper crucible .
Melting temperature is 1850C.
A rotating magnetic field is applied to the molten zone for improved mixing.
Depending on the customer 2 or 3 melting steps are applied.
1st. and 2nd melting occurs under vacuum 10-2 to 10-3 Torr , 3rd melting occurs under
vacuum 10-4 Torr.
Melting requires a lot of practical experience to minimize the radial and longitudinal
variation of alloying elements, since the solubility of the various elements is different
in the liquid and in the solid phase.

Melting of Zr-Alloys by the

Consumable Electrode Process

Zirconium Alloy Fuel Clad Tube - Sandvik Special Metals Corp. (1989) p. 27

Melting of Zr-Alloys by the

Consumable Electrode Process

Source: Framatome-ANP

6t Ingots of Zry-4, as Melted

Western Fabrication Steps from Zr-Alloy Ingot to Final

Products
Hot Deformation
Forging
Extrusion
Beta-Quenching
Cold Deformation

Hot Deformation Beta Quenching

The as cast final ingot has a fusion structure to be deformed

and also has to be reduced to smaller dimensions stepwise.
For this purpose several hot deformations are necessary.
In the West replaced by modern high efficiency hot pre-forging.
These processes reduce the original outer diameter of the final ingot of ~ 630 mm
to finally ~180 mm.
Beta quenching is an essential step for all Zircaloy material production.
It may be performed before the forging or before the hot extrusion.
For tubular material a hot extrusion process is added:
after machining the hot deformed logs into billets with a hole drilled in.
With this process tube hollows are fabricated which are the starting product for the
cold deformation processes ending up as cladding or guide tubes for nuclear fuel.

Hot Deformation
Forging

The finally melted ingot is converted into billets for extrusion by hot forging.
Two processes have to be distinguished :

Forging after heating into the -phase temperature range ( ~1050C),

This process is used for the first steps of heavy reduction of dimensions down to
octagons of ~350 mmm.

Forging after heating into the -phase temperature range ( < 750C)
This process is used for the smaller dimensions. There are two purposes for working
in the -phase temperature range:
breaking the fusion structure to achieve high structural homogeneity, and
achieving a given value for the A parameter (= cummulative annealing
parameter) already in that stage of fabrication, as required by the customer.
This A parameter plays an important role to control the in-pile corrosion of
Zircaloy (-2 and-4). In this case the -quenching is performed before these
forging steps.
41

Hot Deformation
Extrusion
After final forging to ~180 mm diameter the log is being cut and machined
to the size where from the extrusion process starts to form a tube hollow which is
the starting work-piece for the (cladding or guide tube) fabrication by cold
deformation.
The machining comprises the adjustment of the outer diameter by turning and
the drilling of a hole into the billet.
The extrusion process is performed in the -phase temperature range.
There are very strict geometrical requirements like
straightness and wall thickness,
in particular with regard to concentricity,
For cladding tube fabrication today typically
outer diameter between 80 to 85 mm are used and
a high wall thickness, e.g. a dimension like 80 x 14 mm (O.D. x Wall).

42

Consulting Services in the

Area of Zr-Alloy Fabrication

High Load/ High Speed Press Forging

Photos: H.G. Weidinger, by courtesy of Framatome-ANP

43

Beta Quenching Process

Beta-Quenching is one of the most important process steps from alloying/melting to the
finish of the final product.
On one hand, this process step facilitates to make the material forget the influence of all
previous processing. On the other hand, it sets the starting conditions for all
subsequent thermal-mechanical processes which are now all kept within the
temperature range of the alpha-phase.
Beta-quenching consists of the following four equally important process phases:
1.

Heating up
by inductive heating or by radiation heating in an (electrically heated) furnace

2.

Temperature Holding (Soaking) in the beta -phase temperature range (< 1050C)

3.

Transfer from the heating device (electrical furnace, induction heating, etc) to the
quenching facility (water bath)

4.

Quenching, I.e. the material is cooled rapidly from the beta-phase temperature range to
alpha-phase temperature range (room temperature)

KEY PROCESSES
BETA -QUENCHING

Soaking

Transfer

900
800
700
600

++
g
nchin
-Que
Beta

Heating Up

1000

Temperature

500

Time
H. G. Weidinger

Cold Deformation I
From Tube Hollow to Final Tubes:
FR cladding tubes,
Structural tubes, like guide tubes (PWR fuel) or water rods (BWR fuel)
For fabricating cladding tubes
today starting dimensions of 80 to 85 mm O.D are used and
the cold deformation (I.e. rocking = pilgering) occurs in four steps
from tube hollow to final cladding tube.
Important parameters for these cold deformation steps are
the degree of cold work and
the q-factor: wall-thickness : O.D.
After each cold deformation step
an intermediate annealing is necessary to recrystallize the material
that became very hard and brittle during the cold deformation.
Normally an annealing procedure at ~750C/2h is used.
Final fabrication steps are:
final annealing
finishing

Cold Deformation
Pilgering

Source Framaome-ANP/NRG

Cold Deformation Steps to Fabricate Cladding Tubes

old standard fabrication PWR cladding tube

texture

grain size

Q = 1,68
Q = 1,03
e = 81,0%

ASTM Nor. 13

Q = 2,81

4,0 m

e = 76,1%

e = 71,3%

Texture optimized fabrication PWR cladding tube

Q = 1,02

Q = 1,65

grain size

texture

Q = 1,34
Q = 5,9

ASTM No. 13
4,0 m

e = 74,6%

e = 81,9%

e = 69,7%
e = 55,7%

Optimizing the Texture by Modified Pilgering Sequence

M. Perez and S. Reschke; KTG Conference on Material Development for
Fuel Elements in LWR, Karlsruhe, Germany (1993), p. 49 - 78

Alpha-Annealing in Vacuum
Technological Background
for Adequate Vacuum Annealing

Furnace

Retort

Temperature

SoakingTime

Time
Tubes

Schematic Depiction of The Local Difference in Temperature

vs. Time History During Vacuum Annealing of Zircaloy Tubes
H.G.Weidinger

Cold Deformation
Zr Sheet Products
Appliction
Spacer grid prematerial (BWR & BWR fuel structure),
BWR fuel channel sheets
For fabricating sheets
hot deformation (rolling or forging) to starting dimension for
cold deformation (rolling with or without axia stress)) occurs in many steps
Important parameters for these cold deformation steps are
the degree of cold work and
the rolling direction
After each cold deformation step
an intermediate annealing is necessary to recrystallize the material
that became very hard and brittle during the cold deformation.
Normally an annealing procedure at ~750C/2h is used.
Final fabrication steps are:
final annealing
finishing

Zr-Sheet Production

H.G. Weidinger

Basic Process Flow Outline for

Sheet Fabrication from Beta - Quenching

Cold Rolling

Source: Wah Chang

Cold Rolling with Axial Stress