Steel Forgings: Design, Production, Selection, Testing and Application, Manual 53

141 Pages·2005·5.613 MB·English

by  Edward G. Nisbett

Steel :sgnigroF
Design, Production, Selection,
Testing, and Application
Edward G. Nisbett
ASTM Stock No. MNL53
ASTM International
100 Barr Harbor Drive
PO Box C700
West Conshohocken, PA 19428-2959 USA
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Library of Congress Cataloging-in-Publication Data
Nisbett, Edward G.
Steel forgings: design, production, selection, testing, and application / Edward G. Nisbett.
p. cm.
"ASTM Stock No. MNL53.*
ISBN 0-8031-3369-3
1. Steel forgings. I. Title.
TS320.N59 2005
672--dc22
2005020481
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Foreword
THIS PUBLICATION, Steel Forgings: Design, Production, Se/ec- tee 10A on Steel, Stainless Steel and Related Alloys. The author
tion, Testing, and Application, was sponsored by ASTM Commit- is Edward G. Nisbett.
Contents
Chapter 1: Introduction: Why Steel Forgings? ................................................... 1
Chapter 2: Why Use Forgings? .................................................................... 5
Steel Plate ................................................................................... 5
Hot Rolled Bar ................................................................................ 5
Steel Castings ................................................................................ 5
Steel Forgings ................................................................................ 6
Chapter 3: Effect of Steel Making ............................................................... 15
Steel Refining ............................................................................... 15
Ladle Refining Furnace 16
........................................................................
Vacuum Degassing ........................................................................... 16
Steel Cleanliness and Inclusion Shape Control ...................................................... 19
Chapter 4: Forging Ingots ......................................................................... 20
Vacuum Arc Remelting ........................................................................ 20
Electroslag Remelting ......................................................................... 21
Ingot Mold Design, Ingot Production and Segregation ............................................... 22
Forging Stock 22
...............................................................................
Chapter 5: Types of Forging ...................................................................... 24
Open Die Forging ............................................................................ 24
Closed Die Forging 25
...........................................................................
Extrusions 25
..................................................................................
Rotary Forging Machines ...................................................................... 26
Ring Rolling 27
.................................................................................
Forging Reduction 27
............................................................................
Chapter 6: Heating for Forging .................................................................. 32
Heat to Forge Furnaces 32
........................................................................
Reheating 33
..................................................................................
Induction Heating 33
............................................................................
Chapter 7: Post Forge Practices .................................................................. 34
Chapter 8: Machining ............................................................................. 36
Grinding 37
...................................................................................
Chapter 9: Heat Treatment ....................................................................... 40
Annealing
.................................................................................. 40
Micro-Alloyed Forgings
........................................................................ 40
Carbon and Alloy Steel Forgings ................................................................ 40
Heat Treatment Equipment .................................................................... 41
Furnaces 41
..................................................................................
Batch Furnaces ........................................................................... 42
Horizontal Furnaces 42
.......................................................................
Vertical Furnaces ......................................................................... 42
Continuous Furnaces ...................................................................... 43
Induction Heating 43
........................................................................
Controlled Atmosphere/Vacuum Furnaces 43
.....................................................
Cooling/Quench Facilities 43
....................................................................
Liquid Quenching ......................................................................... 43
Water Quenching ......................................................................... 43
Oil Quenching ........................................................................... 45
Polymer Quenching ....................................................................... 45
Polymer Concentrations 45
....................................................................
Spray Quenching 46
.........................................................................
Alternate Heat Treatments ..................................................................... 46
Heat Treatment Rigging ..................................................................... 46
Hot Rigging ............................................................................. 46
Cold Rigging ............................................................................. 48
Tempering .................................................................................. 50
Chapter 10: Mechanical Testing ................................................................... 53
Hardness Testing ............................................................................. 54
Tension Testing .............................................................................. 55
Impact Testing ............................................................................... 57
Fracture Toughness Testing ..................................................................... 57
Fatigue Testing .............................................................................. 57
Chapter 11: Nondestructive Examination ......................................................... 59
Surface Examination .......................................................................... 59
Visual Examination ........................................................................... 59
Magnetic Particle Examination .................................................................. 60
Liquid Penetrant Examination .................................................................. 61
Volumetric Examination ....................................................................... 62
In-Service Inspection .......................................................................... 65
Chapter 12: Surface Treatment .................................................................... 66
Direct Hardening ............................................................................. 66
Nitriding ................................................................................... 67
Gas Nitriding .............................................................................. 68
Ion Nitriding .............................................................................. 69
Carburizing ................................................................................. 69
Salt Bath Treatments .......................................................................... 70
Cold Working ............................................................................... 71
Chapter 13: Manufacturing Problems and Defects .............................................. 72
Base Material Choice .......................................................................... 72
Ingot Defects ................................................................................ 72
Ingots Size and Choice ........................................................................ 74
Billet/Bloom Size and Source ................................................................... 74
Heating for Forging .......................................................................... 75
Induction Heating ............................................................................ 76
Forging Operations and Sequence ............................................................... 76
Machining .................................................................................. 76
Post Forge Handling / Heat Treatment ............................................................ 76
Chapter 14: A Word about ASTM International, Committee A01 on Steel, Stainless Steel,
and Related Alloys, and General Requirement Specifications for Forgings .................. 78
Writing Standards ............................................................................ 78
ASTM International Steel Forging Standards ....................................................... 78
General Requirements Specifications ............................................................. 79
General Requirement Specifications for ASTM Steel Forging Specifications ............................... 79
A 788-04 Steel Forgings, General Requirements .................................................... 79
Specification A 961/A 961M-04a Common Requirements for Steel Flanges, Forged Fittings,
Valves, and Parts for Piping Applications ........................................................ 82
Chapter 15: Steel Forgings for the Fittings Industry ............................................ 84
A 105/A 105M-03, Carbon Steel Forgings for Piping Applications ...................................... 84
A 181/A 181M-01, Carbon Steel Forgings for General Purpose Piping ................................... 85
A 182/A 182M-04, Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and
Valves and Parts for High Temperature Service ................................................... 86
A 350/A 350M-04a, Carbon and Low-Alloy Steel Forgings, Requiring Notch Toughness Testing
for Piping Components ...................................................................... 86
A 522/A 522M-04, Forged or Rolled 8 and 9% Nickel Alloy Steel Flanges, Fittings, Valves, and
Parts for Low-Temperature Service ............................................................. 88
A 694/A 694M-00, Carbon and Alloy Steel Forgings for Pipe Flanges, Fittings, Valves, and
Parts for High-Pressure Transmission Service ..................................................... 89
A 707/A 707M-02, Forged Carbon and Alloy Steel Flanges for Low Temperature Service ................... 89
A 727/A 727M-00, Carbon Steel Forgings for Piping Components with Inherent Notch
Toughness ................................................................................ 89
A 836/A 836M-02, Specification for Titanium-Stabilized Carbon Steel Forgings for Glass-Lined
Piping and Pressure Vessel Service ............................................................. 89
Chapter :61 Forging Related Test Methods 19
......................................................
Magnetic Particle Examination 19
..................................................................
A 275/A 275M-98, Test Method for the Magnetic Particle Examination of Steel Forgings ................. 19
A 966/A 966M-96, Magnetic Particle Examination of Steel Forgings Using Alternating Current ............. 92
A 456/A 456M-99, Magnetic Particle Examination of Large Crankshaft Forgings ........................ 92
A 986/A 986M, Magnetic Particle Examination of Continuous Grain Flow Crankcase Forgings 93
.............
Ultrasonic Examination 93
........................................................................
A 388/A 388M-04, Ultrasonic Examination of Heavy Steel Forgings ................................... 93
A 745/A 745M-94, Ultrasonic Examination of Austenitic Steel Forgings ................................ 95
A 418-99, Ultrasonic Examination of Turbine and Generator Steel Rotor Forgings ....................... 95
A S03/A 503M, Ultrasonic Examination of Forged Crankshafts ....................................... 95
A 531/A 531M-91, Ultrasonic Examination of Turbine-Generator Steel Retaining Rings ................... 96
A 939-96, Ultrasonic Examination from Bored Surfaces of Cylindrical Forgings .......................... 96
General Comments 96
.........................................................................
Portable Testing Hardness Standards 96
.............................................................
A 833, Indentation Hardness of Metallic Materials by Comparison Testers Hardness ...................... 96
A 956-02, Leeb Testing Hardness of Steel Products 97
................................................
Other Portable Testing Hardness Methods ....................................................... 98
Heat Stability Testing 98
.........................................................................
A 472-98, Heat Stability of Steam Turbine Shafts and Rotor Forgings ................................. 98
Macro Structure Tests 99
.........................................................................
A 604-93, Macroetch Testing of ConsumablEel ectrode Remelted Steel Bars and Billets ................... 99
Chapter :71 Steel Forgings for the Pressure Vessel Industry ................................. 100
A 266/A 266M-03, Carbon Steel Forgings for Vessel Pressure Components .............................. 100
A 336/A 336M-04, Alloy Steel Forgings for Pressure and High Temperature Parts ........................ 101
A 372/A 372M-03, Carbon and Alloy Steel Forgings for Thin Walled Vessels Pressure ..................... 201
A S08/A 508M-04b, Quenched and Tempered Vacuum TreateCda rbon and Alloy Steel
Forgings for Vessels Pressure 301
.................................................................
Chemical Composition of Actual Grade 2 Forgings 301
...............................................
Forging Dimensions 103
........................................................................
Heat Treatment
........................................................................... 104
Nil Ductility Test Temperature ASTM (Per Specification 208) E
...................................... 104
A 541/A 541M-9S, Quenched and Tempered Alloy Steel Forgings for Vessel Pressure
Components 104
..............................................................................
A 592/A 592M-04, High Strength Quenched and Tempered Low-Alloy Steel Forged Fittings
and Parts for Vessels Pressure ................................................................ 105
A 649/A 649M-04, Forged Steel Roils Used for Corrugating Paper Machinery ........................... 501
A 723/A 723M-03, Alloy Steel Forgings for High-Strength Pressure ComponentA pplication ................ 106
A 765/A 765M-01, Carbon Steel and Low Alloy Vessel Steel Pressure Component Forgings with
Mandatory Toughness Requirements 107
..........................................................
A 859/A 859M-04, Age Hardening Alloy Steel Forgings for Vessel Pressure Components ................... 108
A 965/A 965M-02, Steel Forgings, Austenitic, for Pressure and High Temperature Parts ................... 108
Chapter :81 Steel Forgings for Turbines and Generators ..................................... 109
A 288-91, Carbon and Alloy Steel Forgings for Magnetic Retaining Rings for Turbine
Generators 109
...............................................................................
A 289/A 289M-97, Alloy Steel Forgings for Nonmagnetic Retaining Rings for Generators .................. 109
A 469/A 469M-04, Vacuum-Treated Steel Forgings for Generator Rotors ............................... 109
A 470-03, carbon and Alloy Steel Forgings for Turbine Rotors and Shafts ................. 111
Vacuum-Treated
A 471-94, Vacuum-Treated Alloy Steel Forgings for Turbine Rotor Disks and Wheels
...................... 113
A 768-95, Vacuum-Treated 12% Chromium Alloy Steel Forgings for Turbine Rotors and Shafts .............. 113
A 891-98, Precipitation Hardening Iron Base Superalloy Forgings for Turbine Rotor Disks and Wheels ........ 311
A 940-96, Vacuum Treated Steel Forgings, Alloy, Differentially Heat Treated, for Turbine Rotors ............ 311
A 982-00, Steel Forgings, Stainless, for Compressor and Turbine Airfoils ................................ 114
Chapter :91 Steel Forgings for General Industry .............................................. 115
A 290-02, Carbon and Alloy Steel Forgings for Rings for Reduction Gears .............................. 115
A 291-03, Steel Forgings, Carbon and Alloy, for Pinions, Gears, and Shafts for Reduction Gears ............. 116
A 427-02, Wrought Alloy Steel Rolls for Cold and Hot Reduction
..................................... 116
A 504/A 504M-04, Wrought Carbon Steel Wheels ................................................. 116
A 521/A 521M-04, Steel, Closed-Impression Die Forgings for General Industrial esU ...................... 117
A 551-94, Steel Tires ......................................................................... 117
A 579/A 579M-04a0 Superstrength Alloy Steel Forgings 711
.............................................
A 646/A 646M-04, Premium Quality Alloy Steel Blooms and Billets for Aircraft and Forgings ...... 118
Aerospace
A 668/A 668M-04, Steel Forgings, Carbon and Alloy for General Industrial esU .......................... 118
A 711/A 711M-04, Steel Forging Stock 119
..........................................................
A 729/A 729M-05, Alloy Steel Axles, Heat-Treated, for Transit Mass and Electric Railway
Service
.................................................................................. 119
A 8371A837M-03. Steel Forgings, Alloy for Carburizing Applications ................................... 120
A 909-03, Steel Forgings0 Microalloy, for General Industrial esU ....................................... 021
A 9831A 983M-040 Continuous Grain Flow Forged Carbon and Alloy Steel Crankshafts for
Medium Speed Diesel Engines ............................................................... 120
A 1021-02, Martensitic Stainless Steel Forgings and Forging Stock for High Temperature
Service
.................................................................................. 122
Chapter 20: The Role of the Purchaser ......................................................... 124
Chapter 21: Forging Failure Analysis ............................................................ 126
Forging ................................................................................... 126
Hydrogen Damage .......................................................................... 126
Fatigue 127
...................................................................................
Chapter 22: Postscript ............................................................................ 131
MNL53-EB/Sep. 2005
:noitcudortnI Why Steel ?sgnigroF
TIlE BEGINNINGS OF TIlE IRON AGE IN AUSTRIA tated the introduction of steam-powered mills that enabled
about 3000 years ago mark the start of iron and steel forging, wrought iron and later steel plates to be hot rolled.
since at that time hot working by hammering was part of The invention of the steam powered forging hammer,
the process for producing wrought iron, and for making credited to James Nasmyth in 1839, met Isambard Kingdom
products in both wrought iron and steel. The crude smelting Brunell's need for 30-in. (750-mm) diameter wrought iron
furnaces using high-grade iron ore, charcoal, and fluxes pro- propeller shaft forgings for the S.S. Great Britain, (Fig. 1.4),
duced small quantities of iron that had to be forge welded a bold stride forward in naval architecture. Nasmyth's paint-
together by hand to produce useful stock. Initially, this was ing of the forging operation for the shafting (Fig. 1.5) also
the main purpose of forging. The hammers used were quite illustrates the use of a porter bar by the forge crew to posi-
substantial, examples weighing about 80 lb (36 kg) having tion the forging, a task that nowadays would be handled by
been found. Hand hammer working by smiths persisted as a manipulator. A forging of this size was well beyond the
the main shaping procedure for iron and steel until the Mid- capabilities of the water powered forging hammers available
die Ages in Europe when lever operated Olivers were intro- at that time. At over 60 ft (18 m) in length the propeller shaft
duced. Several accounts of Olivers [ ]1 have been traced to (Fig. 1.6) is interesting because it was made by joining two
the north of England and one at Beaumarais Castle near An- 30-in. (750-mm) diameter wrought iron stub shafts (that ran
glesey in North Wales in 1335. Their use continued into the in bearings) by a riveted iron cylinder. The wrought iron
eighteenth century. The Oliver consisted of a hammer at- plates used for the cylinder were 6 ft by 2 ft and 1 in. thick
tached to an axle by a long shaft that was tripped by a foot- (1800 x 600 x 25 mm). The four cylinder condensing steam
operated treadle. A swing shaft then rotated the axle and engine developed 1600 horse power (1200 kW) from steam
raised the hammer for the next blow. A sketch (Fig. 1.1) from at 5 psi (35 kPa) raised from salt water. The ship was com-
a book [2] published in 1770 gives some idea of the appa- pleted in Bristol in the South West of England in 1843 and
ratus. As demand and the size of the iron blooms increased, made the first steam powered crossing of the Atlan-
the Olivers were superseded by water-powered tilt hammers. tic-unaided by sails--in 1845 at an average speed of 9.3
The melt and forge shops were generally close together since knots. Incidentally, this ship has been restored and now oc-
both operations went hand-in-glove; hence, the modern con- cupies the original dry dock in Bristol (Fig. 1.7) where she
cept of an integrated melt and forge shop goes back a long was built over 160 years ago.
way. An example of a water-powered tilt hammer at the Ab- Steel forgings, like hot rolled bar and plate, are the prod-
beydale Industrial Hamlet near Sheffield, England is shown uct of hot compressive plastic working used to consolidate
in Fig. 1.2. Another tilt hammer design is shown in Fig. 1.3. and heal as-cast shrinkage voids and porosity, as well as
This used the elastic energy from bending a wooden board break up the as-solidified structure of the product from the
to augment the gravity drop of the hammerhead. steel making furnaces. The availability of the steam hammer
It is generally acknowledged that the industrial revolu- and the ability to work steel under it in different directions
tion started in earnest with the commercial production in gave forgings the integrity that they are known for today.
1775 of James Watt's condensing steam engine. This facili- This improvement in material integrity and the ability to hot
Fig. 1.1raThe Oliver forging hammer.
thgirypoC (cid:14)9 2005 by ASTM lanoitametN1 gro.mtsa.www
Fig. 1.2--Twin water powered tilt hammers at the Abbeydale Industrial Hamlet near Shef-
field, England. This si a restored operating museum facility for demonstrating the art of
scythe-making. The tilt hammers were li~ted by series a of cogs set in iron collars (1) fitted
on the drive shaft (2). sA the shaft rotated the cogs lifted the hammers (6 and 9) and then
fell under gravity on the anvils (3)T.h e shaft was driven by the water wheel through an
oak toothed spur wheel (4). The scythe starting stock )5( consisted of strips of steel that
were heated in a coke or charcoal fired hearth and then forge welded together under the
fast moving Steeling Hammer (6). This operated at 126 blows a minute when the main
shaft rotated at 2 rpm. This forge welding operation produced a "Mood" that was then
cut in half by the shears (7). After reheating the Mood halves were forged again under
the Steeling Hammer to form "Strings" (8) that began to take the shape of scythe a blade.
On further reheating the Strings were forged under the slower running Plating Hammer
(9) at 66 blows/rain to form the scythe blade, or "Skelp." (Courtesy Sheffield City Museums,
Sheffield, UK)
Fig. 1.3--Water powered forging hammer or Tilt Hammer. The cast iron hammer head "A"
weighed about 500 Ib (225 kg), and was attached to a wooden shaft about 9 ft (2.75 m)
long. The opposite end of the shaft was fitted with a cast iron collar (b) that acted a as
pivot. The water wheel drove a large wooden wheel called the "Arm-Case" )F( that was
fitted with projecting iron tipped wooden blocks. As the arm-case rotated, the blocks
engaged the hammer shaft and lifted it against a spring board )c( called a "Rabbet." After
being lifted by the block, the hammer fell under gravity, assisted by the stored energy in
the bent rabbet. The hammer averaged about 120 to 160 blows/min. (From .D Lardner:
Cabinet ,aideapolcyC pp. 86-87, London 1831)
It is not proposed to discuss the various steel making
processes in any great detail here, but it should be noted that
these do have an effect on the properties of the hot worked
material made from them, and influence some differences
between forgings and hot rolled plate. An excellent overview
of steel making and processing is included in a book entitled
ehT Making, Shaping and Treating of Steel [3].
A definition of a forging was written by ASTM Commit-
tee 10A on Steel, Stainless Steel, and Related Alloys and was
published about 40 years ago as ASTM A 509, Standard Def-
inition of a Steel Forging. This was discontinued in 1985
when it was incorporated into ASTM Specification A 788,
Steel Forgings, General Requirements. The current text is
short and is worth repeating here:
Steel Forging--The product of a substantially com-
pressive plastic working operation that consolidates
the material and produces the desired shape. The plas-
tic working may be performed by a hammer, press,
Fig. 1.4~A cross section through the hull of the S.S. Great Britain
forging machine, or ring rolling machine and must
demonstrates the locations of the four cylinders of the Boulton
deform the material to produce an essentially wrought
Watt condensing steam engine, and the chain drive to the fabri-
structure. Hot rolling operations may be used to pro-
cated propeller shaft. To give an idea of scale, the beam of the
duce blooms or billets for reforging. Forgings may be
vessel was 15 ft (15.5 m) and the chain drive wheel had a diameter
of 18 ft (5.5 m) and a width of 38 in. (950 ram). The four cylinder subdivided into the following three classes on the ba-
steam engine had 88 in. (2200 mm) pistons. (Courtesy of The Great sis of their forging temperatures.
Britain Project, Bristol, UK)
i. Hot-worked forgings--forgings produced by
working at temperatures above the recrystalliza-
work the wrought iron or steel close to the required contour tion temperature for the material.
became the attributes associated with forging today. 2. Hot-cold-worked forgings--forgings worked at
At this point it should be noted that cold forging used elevated temperatures slightly below the recrys-
to shape relatively small parts uses hot worked starting tallization temperature to increase mechanical
stock. strength. Hot-cold worked forgings may be made
Fig. 1.S--James Nasmyth's painting of his patented steam hammer forging the propeller
shaft stubs for Isambard Kingdom Brunel's S.S. Great Britain. These were the largest
wrought iron forgings of the day. Notice the manually operated crane, and the porter bar
crew rotating the forging and passing it between the dies. (Courtesy of The British Mu-
seum Science Collection)