\£J5/ SpeCifiCStiOfl Document No.

B5F5
Issue No. S28
General Electric Company
Orders and Correspondence Must
Specify Complete Material Number

Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

EMPIS Material B5F5 identifies chromium-molybdenum-vanadium steel bars and forgings similar to UNS K14675, as
follows:

EMPIS designation Description

B5F5A Chemical base, hot-rolled bars, annealed
B5F5B Hot-rolled bars or forgings, quenched and tempered
B5F5B2 Hot-rolled bars, quenched and tempered, centeriess ground
B5F5B3 Hot-rolled bars or forgings, quenched and tempered, rough-turned or centeriess ground
B5F5B4 Hot-rolled bars, quenched and tempered, centeriess ground
B5F5B11 Hot-rolled bars or forgings, quenched and tempered, magnetic particle sample inspected
for steel cleanliness
B5F5B31 Hot-rolled bars or forgings, quenched and tempered, rough-turned or centeriess ground,
magnetic particle sample inspected for steel cleanliness
B5F5D2 Cold finished, quenched and tempered

ALTERNATE MATERIAL:
For GE Energy Commercial orders, see Specification D50A152 for potential alternate materials.

ABBREVIATIONS:
"Incl" shall signify "include or included."
"Excl" shall signify "exclude or excluded."

REFERENCED DOCUMENTS:
ASTM A 751 Standard Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
ASTM A 700 Standard Practice for Packaging, Marking , and loading Methods for Steel Products for
Domestic Shipment
ASTM A 193 Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for High
Temperature or High Pressure Service and Other Special Purpose Applications
ANSI B46.1 Surface Texture (Surface Roughness, Waviness, and Lay)
SAE AMS 2301 Steel Cleanliness, Aircraft Quality Magnetic Particle Procedure
SAE AMS 2640 Magnetic Particle Inspection
GE Energy specification:
D50A152 Alternate Material Approved for Manufacture of Power Generation Commercial Orders

CHEMICAL COMPOSITION: % (Heat analysis) (1) (2)

Carbon 0.42-0.50
Manganese 0.45-0.70
Phosphorus, max 0.015 (Forgings) 0.025 (Bars)
Sulfur, max 0.015 (Forgings) 0.025 (Bars)
Silicon 0.20-0.35
Chromium 0.80-1.15
Molybdenum 0.45-0.65
Vanadium 0.25-0.35
Aluminum, max 0.015

(1) Unless otherwise specified, the following residual elements shall be reported for forgings:
Copper, max 0.35
Nickel, max 0.25
(2) Calcium metal, calcium containing ferro-alloys or compounds containing calcium may be added to the molten steel in
the ladle. After solidification, inclusions resulting from the additions shall be spherical in configuration. Stringer-
type inclusions containing calcium are unacceptable.

The heat analysis (formerly ladle analysis) made by the manufacturer to determine the percentages of the elements required
under this specification shall be reported to the purchaser or his representative in a certificate of test when specified on
purchase order or otherwise.

A product analysis (formerly check analysis) may be made by the purchaser from a sample representing each melt. The
chemical composition thus determined shall conform to the requirements of this specification within the permissible
variation for product analysis shown in ASTM A 193 Grade B16.

(Page 1 of 10)

April 30, 2006 Supersedes: B5F5-S27 CAGE IDENT NO. 4B138

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

MECHANICAL PROPERTIES:

Outside diameter Tensile Yield Elongation Reduction Charpy Hardness, max

or overall strength, strength, in 2 inch, of area impact (5) HB, HRC,
thickness, inch ksi, min ksi, min %, min %, min ft-lb, min (6) (Brinell) (Rockwell)
B5F5A:
All 229
B5F5B, B3, B11.B31.D2:
Up to 3 incl 120 105(3) 18 50 302 (7) -
Over 3-5 incl 110 95(3) 17 45 293
Over 5 100 85(3) 16 45 25 293
B5F5B2:
Up to 1/2 incl 120 105(3) 18 50 C32
B5F5B4:
Up to 1 incl 165 145 (4) 14 35 C42

(3) Based on 0.02% offset.

(4) Based on 0.01% offset.
(5) V-notch specimen.
(6) Charpy impact tests required only for rolled bar over 7 inch diameter.
(7) Forgings shall be 293 HB (Brinell) maximum.

MECHANICAL TESTING-BARS:
Test specimens - Test specimens may be taken from any bar. The axis of the specimen shall be located at the center of
bars not over 1 1/2 inch in diameter or width. From round, hexagon or square bars, more than 1 1/2 inch in diameter or
width, the axis of the specimen shall be located midway between the center and the surface of the bar. From rectangular
bars more than 1 1/2 inch wide, the axis of the specimen shall be located midway between the surface bounding the
thickness of the bar and midway between the center and the edge of the bar.
Number of tests - Two tension tests shall be made from each tempering charge. If more than one quenching charge is
represented in a tempering charge, two tension tests shall be made from each quenching charge. If more than one melt
is represented in a quenching charge two tension tests shall be made from each melt. When heat treated without
interruption in continuous furnaces, the material in a lot shall be the same heat, same prior condition, same size, and
subjected to the same heat treatment. Not fewer than two tension tests shall represent a lot selected on the basis of one
tension test from each 10,000 pounds.

MECHANICAL TESTING-FORGINGS:
Test specimen orientation - Unless otherwise specified, the longitudinal axis of test specimens shall be parallel to the
direction of major working of the forging. For upset-disc forgings the longitudinal axis of the test specimens shall be in the
tangential direction.
Specimen location - The longitudinal axis of the specimen shall be located midway between the parallel surfaces of the test
extension if added to the periphery of disks or midway between the center and surface of solid forgings. For hollow
forgings, the longitudinal axis of the specimens shall be located midway between the center and outer surfaces of the
wall. When separately forged test blocks, as defined herein, are employed, the tension test specimens shall be taken
from a location which represents the midwall of the heaviest section of the production forgings. When specimens are
required from opposite ends, they shall be taken from the diagonal corners of an axial plane.
Separate test specimens - When specified in writing, test specimens may be machined from a specially forged block suitably
worked and heat treated with the production forgings. The test block shall be obtained from an ingot, slab, or billet from
the same heat used to make the forgings it represents. This block shall receive essentially the same type of hot working
and forging reduction as the production forgings; however, a longitudinally forged bar with dimensions not less than T by
T by 3T may be used to represent a ring forging. The dimension T shall be a representative of the heaviest effective
cross section of the forging. Separately forged tests blocks are not allowed to represent forgings which require tests at
both ends.
Number of tests - Forgings weighing 100 lb or less at the time of heat treatment require a tension test taken from two
forgings which represent the heaviest forgings, per heat in each 5000 lb weight of forgings in a heat treatment charge.
When heat treatment is performed in continuous-type furnaces with suitable temperature controls and equipped with
recording pyrometers so that complete heat treatment records are available, a heat treatment charge may be considered
as any continuous run not exceeding an eight hour period or 5000 lb of forgings heat treated.
Single tests - Forgings weighing over 100 lb to 2000 lb at the time of heat-treatment, but not exceeding 10 ft in length,
require one tension test taken from each forging. Unless otherwise specified, forgings exceeding 2000 lb or over 10 ft in
length at the time of heat-treatment require two tension tests from each forging, taken 180° apart.

Specification General Electric Company April 30, 2006

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

MECHANICAL TESTING-GENERAL:
Retests - If any test specimen shows defective machining or develops flaws, it may be discarded and another specimen
substituted. If the percentage elongation of any test specimen is less than that specified and any part of the fracture is
more than 3/8 of the gage length from the middle of the gage length, as indicated by scribe scratches marked on the
specimen before testing, a retest shall be allowed.
Reporting - Mechanical tests reported in the certificate of test shall be performed on the bar material after all manufacturing
operations, which can affect the mechanical properties and microstructure of the bar, have been completed. Such
operations include bar straightening and stress relief anneal treatments.

ADDITIONAL REQUIREMENTS:
Process - Shall be made by the electric furnace, basic oxygen, or open-hearth process. Secondary refining and ladle
processing methods are acceptable.
Discard - A sufficient discard shall be made from each ingot to ensure freedom from injurious piping and undue segregation.
Imperfections - Material shall be free from injurious external and internal imperfections such as piping, cracks, fissures, etc.,
which will interfere with the purpose for which it is intended.
Straightening and cold working - Unless otherwise approved by the purchaser, all cold working and straightening shall be
performed prior to the final heat treatment or stress-relief anneal cycle. (See stress-relief anneal below.) Prior approval
is required before straightening EMPIS Material B5F5B4 stock over 1/2 inch thick.
Magnetic Particle Inspection (MPI), (EMPIS Materials B5F5B11 and B31) - Material ordered by Schenectady Turbine
Business Operations, for commercial application to EMPIS designations B5F5B and B5F5B3, and material ordered to
B5F5B11 and B5F5B31, shall be magnetic particle inspected using the direct current, continuous wet method in
accordance with the requirements of AMS 2301 and AMS 2640. Sampling and testing, plus acceptance and reporting,
shall be in accordance with AMS 2301, aircraft quality steel cleanliness.

HEAT TREATMENT:
Heat treatment - EMPIS Materials B5F5B, B2, B3, B11, B31 and D2 shall be heat-treated as follows:
Oil quench 1700-1750 °F
Water quench is permissible on bar sizes over 7 inch diameter if deemed necessary to meet required Charpy impact
properties.
Temper 1200°Fmin
EMPIS Material B5F5B4 shall be heat-treated by oil quenching from 1700-1750 °F and tempering at a temperature suitable
to meet the mechanical properties specified above.
Stress-relief- Bars of EMPIS Materials B5F5B, B2, B3, B11, B31 or D2 which are straightened by any method, including
localized gag or press straightening, requires a stress relief following the final straightening operation. The stress relief
shall not be lower than 100 °F below the final tempering temperature (1100 °F minimum). If straightened, B5F5B4 shall
be stress-relievedat a temperature not exceeding the tempering temperature.

IDENTIFICATION:
Bars - Unless otherwise specified on the purchase order, heat numbers shall be stamped on each bar whenever an extra
charge is not incurred. Those sizes which incur an extra charge shall be tagged or bundled and tagged with the heat
number.
Forgings - Each forging shall be legibly marked by stamping on the end with steel figures with the order number, the drawing
number and the manufacturer's serial or identifying number.

REFEREE METHODS:
Chemical composition ASTM A 751
Tension test ASTM A 370
Charpy impact (V-notch) ASTM A 370
Brinell hardness (8) ASTM A 370
Rockwell hardness ASTM A 370
Magnetic Particle Inspection, direct current AMS 2301 and AMS 2640

(8) Hardness - All readings shall be taken on a flat surface, ground from the periphery or on the end. These
readings shall be taken on the surface for B5F5A and all bars up to 1 1/2 inches in diameter or thickness.
Readings on all other bars shall be taken midway between the center and surface.

Specification General Electric Company April 30, 2006

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

TOLERANCES:
Diameter, thickness and width: (B5F5A, B and B11 - hot-rolled bars, heat-treated)

ROUNDS AND SQUARES

Specified size, inch Tolerance, inch

Out of round
Over To incl Over Under orsquare(9)(10)
5/16 0.005 0.005 0.008
5/16 7/16 0.006 0.006 0.009
7/16 5/8 0.007 0.007 0.010
5/8 7/8 0.008 0.008 0.012
7/8 0.009 0.009 0.013
1 1/8 0.010 0.010 0.015
1 1/8 1 1/4 0.011 0.011 0.016
1 1/4 1 3/8 0.012 0.012 0.018
1 3/8 1 1/2 0.014 0.014 0.021
1 1/2 2 1/64 1/64 0.023
2 2 1/2 1/32 0 0.023
2 1/2 3 1/2 3/64 0 0.035
3 1/2 4 1/2 1/16 0 0.046
4 1/2 5 1/2 5/64 0 0.058
5 1/2 6 1/2 1/8 0 0.070
6 1/2 8 1/4 5/32 0 0.085
8 1/4 9 1/2 3/16 0 0.100

(9) Out-of-round is the difference between the maximum and minimum diameters of the bar, measured at the
same cross section.
(10) Out-of-square is the difference in the two dimensions at the same cross section of a square bar, each
dimension being the distance between opposite sides.

HEXAGONS AND OCTAGONS

Size:
Specified size, inch Size tolerance, inch
Over To incl Over Under Dif 3meas(11)
1/2 0.007 0.007 0.011
1/2 1 0.010 0.010 0.015
1 1 1/2 0.021 0.013 0.025
1 1/2 2 1/32 1/64 1/32
2 2 1/2 3/64 1/64 3/64
2 1/2 3 1/2 1/16 1/64 1/16

(11) Hexagons only.

FLATS

Specified Tolerance,
width, inch width, inch Tolerance, thickness, over or under, inch
0.203 to 0.230 to 1/4 to Over 1/2 Over1 Over 2 Over 3
0.230 1/4 1/2 to1 to 2 to 3 inch
Over To Over Under inch inch inch inch inch inch thick
incl thick, thick, thick, thick, thick, thick,
excl excl incl incl incl incl
1 1/64 1/64 0.007 0.007 0.008 0.010
1 2 1/32 1/32 0.007 0.007 0.012 0.015 1/32
2 4 1/16 1/32 0.008 0.008 0.015 0.020 1/32 3/64 3/64
4 6 3/32 1/16 0.009 0.009 0.015 0.020 1/32 1/16 1/16
6 8 1/8 (12) 3/32 (12) 0.015 0.016 0.025 1/32 1/16

(12) Shall not apply to flats over 3 inches thick.

Specification General Electric Company April 30, 2006

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

TOLERANCES: (Continued)
Diameter, thickness and width: (B5F5B, B3, B31)
Forgings shall be reasonably close to the dimensions specified on purchase order or drawing accompanying the order.
Forgings shall permit machining to specified finished dimensions in clean bright metal without the removal of excessive
amounts of metal.

Length: (B5F5A, B and B11 - hot-rolled bars, heat-treated)

HOT SHEARED FORMS

Specified size
of round, square, Tolerance, plus, inch, no tolerance minus
hexagon, octagon, 5 to 10 ft 10 to 20 ft 20 to 30 ft 30 to 40 ft 40 to 60 ft
inch long, excl long, excl long, excl long, excl long, incI
To 1 incI 1/2 3/4 1 1/4 1 3/4 2 1/4
Over 1 to 2 incI 5/8 1 1 1/2 2 2 1/2
Over 2 to 5 incI 1 1 1/2 1 3/4 2 1/4 2 3/4
O v e r 5 t o 9 1/2incl 2 2 1/2 2 3/4 3 3 1/4

Flats:

Specified size of flats, inch Tolerance, plus, inch no tolerance minus

5 to 10 ft 10 to 20 ft 20 to 30 ft 30 to 40 ft 40 to 60 ft
Thickness Width long, excl long, excl long, excl long, excl long, incI
To 1 incI To 3 incI 1/2 3/4 1 1/4 1 3/4 2 1/4
Overl To 3 incI 5/8 1 1/2 2 2 1/2
To 1 incI Over 3 to 6 incI 5/8 1 1/2 2 2 1/2
Overl Over 3 to 6 incI 1 1 1/2 1 3/4 2 1/4 2 3/4
To 1 incI Over 6 to 8 incI 3/4 1 1/4 1 3/4 3 1/2 4
Over 1 to 3 incI Over 6 to 8 incI 1 1/4 1 3/4 2 3 1/2 4

Diameter: (B5F5B2, B4)

Up to 1/2 inch diameter, inch ± 0.0005
Over 1/2 to 1 inch diameter, inch + 0.002, -0.000

Diameter (centerless ground): (B5F5B3, B31) Diameter (rough turned): (B5F5B3, B31)

Diameter, Tolerance, inch Diameter, Tolerance, inch

inch Over Under inch Over Under
Up to 1 1/8 excl 0.000 0.002 1 1/2-2 incI 0.000 0.018
Over 2-4 incI 0.000 0.022
Over 4-6 incI 0.000 0.026
Over 6-7 3/4 incI 0.000 0.034

Diameter: (B5F5D2)

Diameter, inch Tolerance, inch,

Over Toincl minus only
1 0.007
1 2 0.009
2 4 0.011
4 6 0.013
6 7 3/4 0.017

Length: (B5F5B2, B3, B4, B31, D2)

Random:
ALL FORMS

Length, ft Length range, inch

5 to 20 incI 24
Over 20 to 30 incI 36
Over 30 to 40 incI 48

Specification General Electric Company April 30, 2006

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

TOLERANCES: (Continued)
Diameter: (B5F5D2) (Continued)
Specific: (Machine cut)

ALL FORMS

Diameter or distance
between parallel Length tolerance, inch
surfaces, inch Upto12feetincl Over 12 to 25 feet incl
Over Toincl Plus Minus Plus Minus
3 3/16 1/16 1/4 1/16
3 6 1/4 1/16 3/8 1/16
6 3/8 1/16 1/2 1/16

Straightness: (All material)

1/8 inch in any 5 feet may not exceed 1/8 inch x

CERTIFICATE OF TEST:
When requested, the supplier shall submit promptly to the purchaser at the point of delivery a certificate of test showing the
results of tests for chemical analysis and properties required by this specification. This certificate shall be addressed to
the section, unit or person specified on the purchase order, and shall contain the EMPIS designation, the purchase order
number, and the quantity shipped so that the certificate may be identified with the shipment. In addition, the certificate
shall contain the heat number, size, weight and record of heat treatment, i.e. quench, draw and stress-relief temperatures
and times at temperature.

PACKING AND MARKING:

All material shall be separated by size for shipment, and carefully packed in accordance with ASTM A 700 in such a
manner to avoid damage or loss during shipment. When lift size is not specified on the purchase order, standard AISI lift
will be acceptable.
Each shipment shall be legibly marked with the weight, the purchase order number, the manufacturer's name, and the
EMPIS designation.

Specification General Electric Company April 30, 2006

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

APPENDIX

Included herein are some modified portions of AMS 2301 and AMS 2640 applicable to the magnetic particle testing of bars as
required for EMPIS Material designations B5F5B11 and B5F5B31.

SAMPLING:
Heat qualification:
Heats of top-poured ingots:
Samples shall be taken from semi-finished or finished product representing the top and bottom of the first ingot and
last usable ingot from heats having not more than 10 ingots or not over 30 tons or from portions of heats within
these limits; and from the top and bottom of the first, middle, and last usable ingot of heats having more than 10
ingots or over 30 tons.
Heats of bottom-poured ingots:
Samples shall be taken from semi-finished or finished product representing the top and bottom of three ingots. One
ingot shall be taken at random from the first usable plate (ingot cluster) poured, one ingot at random from the
usable cluster poured nearest to the middle of the heat, and one ingot at random from the last usable cluster
poured. When a heat is constituted by two usable clusters, two of the sample ingots shall be selected from the
second usable cluster poured. When a heat consists of a single usable cluster, any three random ingots may be
selected.
Less than three ingots:
If there are less than three ingots in the heat, samples shall be taken representing the top and bottom of all ingots.
Strand-cast heats:
Samples shall be taken from semi-finished or finished product having at least 3:1 reduction in cross-section from the
cast strand (or samples of the as-cast strand similarly reduced) representing the front, middle, and back of both
strands when two strands are cast, or of an inside strand and an outside strand when more than two strands are
cast. When a single strand is cast, six samples having at least a 3:1 reduction from the cast strand (or samples of
the cast strand similarly reduced) representing both ends of the first, middle, and last usable cuts (blooms) of the
strand or product shall be taken.
Product qualification:
Samples shall be taken at random from not less than 10 percent of the pieces of each lot. A lot shall be all product of
one size from one heat in one shipment. Not less than 3 nor more than 10 samples shall be selected from a lot,
except that if the quantity in the lot is three pieces or less, 1 sample shall be taken from each piece.
Round car test sections:
Solid product over 36 sq inch cross-sectional area:
A quarter-section shall be cut from the sample sufficiently oversize that the center of the original specimen will be
approximately on the surface of the specimen after generating to test size. The specimen shall be converted into
test size by machining, or forging and machining, to a diameter not larger than 6 inches consistent with the
machining allowance specified. As an alternate method when agreed upon by purchaser and supplier, the full
section may be rolled or forged to a 6 inch round or square and an oversize quarter obtained. The identity for
specimen surface representing center of original stock shall be maintained throughout machining and testing.
Solid product 16-36 sq inch, incl, in cross-sectional area:
A quarter-section shall be cut sufficiently oversize that the center of the original specimen will be approximately on the
surface of the sample after generating to test size. The specimen shall be converted to test size by machining, or
forging and machining, to the largest possible round consistent with the surface representing center of original
stock shall be maintained throughout machining and testing.
Solid product less than 16 sq inch in cross-sectional area except flat bars, slabs, and plates:
The specimens shall be machined, consistent with the machining allowance specified, to straight cylindrical samples.
As an alternate method, when agreed upon by purchaser and supplier, a stepdown specimen shall be generated in
equal length circumferential steps as in the Table consistent with the machining allowance specified.

Nominal diameter or distance Step diameter

between parallel sides, inch Step length,
inch 1 2 3 4 5
From 0.25 to 0.50 incl 5.000 D
Over 0.50 to 0.75 incl 2.500 D 2/3D
Over 0.75 to 1.00 incl 1.665 D 3/4D 1/2D
Over 1.00 to1.50 incl 1.250 D 4/5D 3/5D 2/5D
Over 1.50 to 4.00 incl 1.000 D 4/5D 3/5D 2/5D 1/5D

FLAT BAR TEST SPECIMENS:

The type of test, specimen and location in the section shall be as agreed upon by purchaser and supplier.

Specification General Electric Company April 30, 2006

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

ROUGH MACHINING:
Round bars:
The converted sample shall be machined to conform to the allowance of the Table below for surface removal, allowing
0.010 inch per side for finish machining after heat treatment.
Nominal diameter or distance Minimum stock removal,
between parallel sides, inch inch per side
From 0.25 to 0.50 IncI 0.030
Over 0.50 to 0.75 IncI 0.045
Over 0.75 to 1.00 IncI 0.060
Over 1.00 to 1.50 IncI 0.075
Over 1.50 to 2.00 incl 0.090
Over 2.00 to 2.50 IncI 0.125
Over 2.50 to 3.50 IncI 0.156
Over 3.50 to 4.50 IncI 0.187
Over 4.50 to 8.00 IncI 0.250

Flat bars:
Allowance of 20 percent of the nominal thickness or 0.100 inch whichever is less, shall be made for minimum stock
removal, allowing 0.010 inch per side for finish machining after heat treatment.

HEAT TREATING:
If not already fully heat treated, rough machined samples shall be hardened by austenitizing, quenching and tempering to
produce a Brinell hardness of 250 HB minimum.

FINISH MACHINING:
The heat treated specimens shall be finished machined to surface texture not rougher than 40 microinches AA, determined in
accordance with ANSI B46.1. Rateable surface of specimens shall be nominally 5 inch in length. The ends of the
specimen shall be finished to provide good electrical contact.

INSPECTION:
Magnetic particle inspection shall be performed in accordance with AMS 2640 by the circular, wet, continuous method using
800-1200 amperes per inch (32 to 48 amperes per millimeter) of diameter. If the stepdown bar is used, the smallest step
shall be magnetized and inspected first; the larger steps shall be magnetized and inspected individually in succession of
increasing size until all steps have been evaluated.
Cleanliness standards cover nonmetallic inclusions only. Material which, during inspection, reveals indications representing
actual ruptures, such as cracks, seams, laminations, and laps, will be subject to rejection except where these indications
result from sample preparation.
The results of magnetic particle inspection shall be appropriately recorded. All recorded results shall be identified, filed, and
made available to the purchaser upon request.

EVALUATION OF STEEL CLEANLINESS:

After inspection, each indication 1/16 inch and over in length shall be recorded. The frequency (number) and severity (size)
of the indications shall be calculated as follows:
Frequency (FY.
Total the number of indications per test specimen.
The frequency per specimen is determined by dividing the total number of indications for each specimen by the
area of the test specimen in square inches.
The frequency ratings for all test specimens from a heat are totaled.
The average frequency (F) equals the total frequency rating for all test specimens from a heat divided by the
number of test specimens.
Severity ($):
Record the length of each indication.
The product for each specimen is computed by totaling the product of the number of indications times the
appropriate progression factor listed in the following table:

Length of indication, inch Progression factor

Over for severity rating

From 1/16 to 1/8 IncI 0.5

Over 1/8 to 1/4 IncI 1
Over 1/4 to 1/2 IncI 2
Over 1/2 to 3/4 IncI 4
Over 3/4 to 1 IncI 8
Over 1 to 1 1/2 IncI 16

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Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

EVALUATION OF STEEL CLEANLINESS: (Continued)
After inspection, each indication 1/16 inch and over in length shall be recorded. The frequency (number) and severity (size)
of the indications shall be calculated as follows:(Continued)
Severity ($): (Continued)
The severity per specimen is determined by dividing the product for each specimen by the area of the specimen in
square inches.
The severity ratings for all test specimens from a heat are totaled.
The average severity (S) equals the total severity rating for all test specimens from a heat divided by the number of
test specimens.

DISPOSITION:
Product inspected in accordance with this specification shall conform to the following maximum frequency and severity
ratings.

Heat qualification:

Rating
Sample Frequency Severity
Individual test bar 0.67 0.55
Average of all bars from heat 0.34 0.25

Product qualification:

Rating
Sample Diameter, inch Frequency Severity
Individual bar Less than 2.5 1.00 0.95
Individual bar Over 2.5 incl 0.80 0.67
Average of all bars 1.0 to 2.5 incl 0.85 0.80
Average of all bars Over 2.5 to 4.0, incl 0.55 0.50
Average of all bars Over 4.0 0.34 0.25

Product under 1.0 inch in nominal diameter or distance between parallel sides inspected using the
straight cylindrical test bars or product less than 16 sq inch in cross-sectional area inspected by
the alternate step-down specimen shall have maximum average frequency and severity ratings as
agreed upon by purchaser and supplier.

TESTING AND REPORTING:

Responsibility for inspection:
The supplier shall provide all the required test samples and shall be responsible for performing required tests. Results of
such tests shall be reported to the purchaser. Purchaser reserves the right to sample and to perform any confirmatory
testing deemed necessary to ensure that the product conforms to the requirements of this specification.
Classification of tests:
Tests to determine conformance to all applicable requirements of this specification are classified as acceptance tests.
Heat qualification:
Tests to determine conformance to "heat qualification" requirements, if acceptable, need be conducted only once per
heat. Heats which have been qualified as semi-finished product shall be considered qualified for finished product.
Product qualification:
Tests to determine conformance to the requirements of this specification on product not "heat qualified" shall be
conducted on product of each size and shape of each lot made from each heat.
Sampling:
The sampling shall be performed by the producer for heat qualification. No further sampling by the producer shall be
required from a heat which meets the requirements. Sampling procedure on the product shall be as described.
Reports:
The vendor of the product shall include the frequency severity rating for each lot in the shipment in addition to other
information required by the applicable material specification.

Specification General Electric Company April 30, 2006

B5F5-S28
Page 10

Bars & Forgings, Alloy Steel; Chromium-Molybdenum-Vanadium

RESAMPLING AND RETESTING:
Retests:
If any specimen used in the above tests fails to meet the specified requirements, disposition of the heat or lot may be
based on the results of testing three additional specimens for each original nonconforming specimen; additional
specimens shall be as follows:
Heats of top-poured ingots:
One of the additional specimens shall be taken from the same position from product from each of the two
available ingots most immediately adjacent in pouring sequence to that from which the originally
nonconforming specimen was taken. The third specimen shall be taken from product of the original
nonconforming ingot after additional discard. Should the latter specimen be unacceptable, resampling and
retesting of the nonconforming ingot may be repeated after as many consecutive discards as necessary to
obtain acceptable results. Should any of the adjacent ingot tests fail to meet the specified requirements,
resampling and retesting of these ingots will be permitted using the procedure specified for the original
nonconforming ingot.
Heats of bottom-poured ingots:
One of the additional specimens shall be taken from the same position from product from each of the two
available ingots most immediately adjacent to that from which the originally nonconforming specimen was
taken. The third specimen shall be taken from product of the original nonconforming ingot after additional
discard. Should the latter specimen be unacceptable, resampling and retesting of the nonconforming ingot
may be repeated after as many consecutive discards as necessary to obtain acceptable results. Should
any of the adjacent ingot tests fail to meet the specified requirements, resampling and retesting of those
ingots will be permitted using the procedure specified for the original nonconforming ingot.
Less than three ingots:
If there are less than three ingots in the heat, all tests locations that fail will be retested after discard is taken.
Strand cast heats:
One of the additional samples shall be taken from the section adjacent to the original nonconforming specimen
after sufficient discard, and the two adjacent cuts (blooms) shall be sampled at both ends and tested.
Should any of the adjacent cut (bloom) test locations fail to meet the specified requirements, resampling
and retesting of those locations will be permitted using the procedure specified for the original
nonconforming location.

DOCUMENT REVISION STATUS:

Rev Description Rev date
524 (Interim Status) 1995 Aug 14
525 Added Note (2) regarding Fitchburg Navy and Small Steam Turbine 1995 Oct 31
526 Added Modulus of Elasticity, Coefficient of Thermal Expansion and Thermal Conductivity 1999 Oct 31
527 Added Note (3) reference to ASTM A 193 and added designations B and B3 2001 May 31
528 Added approved alternate materials for GE Energy. Removed Notes (1), (2), and (3).
Added referenced documents. 2006 Apr 30

Specification General Electric Company April 30, 2006