ATI 304B7 P/M™ Alloy
Technical Data Sheet
ATI NuShield™ Borated Stainless Steels
ATI 304B7 P/M™ Borated Stainless Steel
(UNS S30467)
INTRODUCTION
The ATI NuShield™ family of borated stainless steels offer the superior performance of powder metallurgy processing.
The uniform, fine dispersion of boron containing particles resulting from the P/M process imparts superior neutron
absorption and enhanced toughness and ductility.
GENERAL CHARACTERISTICS
ATI 304B7 P/M™ Alloy (UNS S30467) is a boron containing stainless steel
with boron content between 1.75 and 2.25 weight %.
The alloy has an optimum microstructure and properties imparted by
powder metallurgy processing. A typical SEM micrograph
may be seen below. The microstructure consists of chromium rich boride
particles (darker phase) in an austenite matrix. The
composition and properties of the alloy conform to Specification ASTM
A887-89 for 304B7 Grade A.
APPLICATIONS
Borated stainless steels are widely used for applications where neutron
absorption is needed. The high strength and good ductility of borated
stainless steels make them attractive for structural applications where other neutron absorbing materials lack the necessary
properties. Typical applications include racks for wet storage of used nuclear fuel, baskets for casks used for dry storage of used
nuclear fuel, glove box components, and general reactor shielding. ATI 304B7 P/M™ Alloy is available as sheet and plate products.
Composition of ATI 304B7 P/M™ Alloy (ASTM A887 – 89 Limits)
Element
Weight Percent ASTM A887 – 89
Carbon
0.08 max
Manganese
2.00 max
Phosphorous
0.045 max
Sulfur
0.030 max
Silicon
0.75 max
Chromium
18.00 – 20.00
Nickel
12.00 – 15.00
Boron
1.75 – 2.25
Nitrogen
0.10 max
Cobalt
0.2 max
Iron
Balance
Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification
or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or
warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown
herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a
registered trademark of ATI Properties, Inc. © 2013 ATI. All rights reserved.
VERSION 1 (6/20/2013): PAGE 1 of 5
Allegheny Technologies Incorporated
1000 Six PPG Place
Pittsburgh, PA 15222-5479 U.S.A.
www.ATImetals.com
ATI 304B7 P/M™ Alloy
Technical Data Sheet
SPECIFICATION COVERAGE
ATI 304B7 P/M™ (UNS S30467) alloy is covered by ASTM standard A887–89 “Borated Stainless Steel Plate, Sheet, and Strip
for Nuclear Application”, as Grade A material.
MECHANICAL PROPERTIES
Typical mechanical properties of ATI 304B7 P/M™ Alloy along with the ASTM 887-89 values are listed in the table below.
Form
UTS MPa (ksi)
YS MPa (ksi)
%El
Impact J (ft-lb)
Sheet1
758 (110)
335 (48)
19
N/A
Plate2
738 (107)
338 (49)
24
22 (16)
ASTM 887-89 304B7
Grade A
515 (75) min
205 (30) min
17.0 min
14 (10) min
1- Typical expected properties for sheet ≥ 2mm (0.0787 inches) thickness.
2- Typical expected properties for hot-rolled plate between 5mm (0.197 inches) and 12mm (0.472 inches) thickness.
PHYSICAL PROPERTIES
Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification
or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or
warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown
herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a
registered trademark of ATI Properties, Inc. © 2013 ATI. All rights reserved.
VERSION 1 (6/20/2013): PAGE 2 of 5
Allegheny Technologies Incorporated
1000 Six PPG Place
Pittsburgh, PA 15222-5479 U.S.A.
www.ATImetals.com
ATI 304B7 P/M™ Alloy
Technical Data Sheet
Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification
or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or
warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown
herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a
registered trademark of ATI Properties, Inc. © 2013 ATI. All rights reserved.
VERSION 1 (6/20/2013): PAGE 3 of 5
Allegheny Technologies Incorporated
1000 Six PPG Place
Pittsburgh, PA 15222-5479 U.S.A.
www.ATImetals.com
ATI 304B7 P/M™ Alloy
Technical Data Sheet
Property
English Units
SI Units
3
Density
0.280 lb/in
Electrical Resistivity
29.1 micro-ohm · in
7.74 g/cm
74 micro-ohm · cm
3
Modulus of Elasticity
3
30.5 x 10 ksi
210 GPa
CORROSION RESISTANCE
The addition of high levels of boron to stainless steels reduces the corrosion resistance to some environments. However,
laboratory testing in simulated spent fuel pool waters, containing 13,000 ppm boric acid and 10 ppm Cl- showed no attack. No
significant corrosion of borated stainless steels has been reported in spent fuel applications.
CORROSION TEST RESULTS:
Modified ASTM G 48 Practice B Crevice Test and Practice A Pitting Test 10 ppm Cl- (as NaCl) & 13,000 ppm Boric Acid
Solution 72 Hours at 24°C.
Modified G48 Practice B
Modified G48 Practice A
2
Wt. Loss (g/cm )
Pitting
Wt. Loss (g/cm2)
Pitting
0.000009
None
0.000013
None
0.000010
None
0.000010
None
Photograph of ATI 304B7 P/M™ Samples after modified G48 testing. No attack was observed.
FABRICATION
Welding
ATI 304B7 P/M™ Alloy is generally weldable using standard techniques. However, some degradation in properties of the heat
affected zone should be expected. The use of AWS ER 308/309 filler metal is recommended for best results. Low heat inputs
should be used to minimize base metal dilution.
Formability
ATI 304B7 P/M™ Alloy can be cold formed by bending although the angle and radius may be limited. The edges should be
ground and free of area of stress concentration such as gouges, burrs, dents, etc. Some bend test data for ATI 304B7 P/M™
Sheet may be seen below.
Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification
or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or
warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown
herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a
registered trademark of ATI Properties, Inc. © 2013 ATI. All rights reserved.
VERSION 1 (6/20/2013): PAGE 4 of 5
Allegheny Technologies Incorporated
1000 Six PPG Place
Pittsburgh, PA 15222-5479 U.S.A.
www.ATImetals.com
ATI 304B7 P/M™ Alloy
Technical Data Sheet
Bend testing results for 3mm-thick ATI 304B7 P/M™ Sheet
Test Specimen
Transverse
Longitudinal
12.7mm radius to 90º
Pass
Pass
12.7mm radius to 180º
Pass
Pass
6.4mm radius to 90º
Pass
Pass
6.4mm radius to 180º
110º
Pass
3.2mm radius to 90º
83º
77º
Photograph of 3mm-thick ATI 304B7 P/M™ Sheet bent to 180° at a radius of 6.4mm (0.25") and 12.7mm (0.5").
HEAT TREATMENT
Hot working should be performed between 1700°F (927°C) and 2000°F (1093°C). To restore properties, hot or cold worked
products should be annealed at a temperature range of 1900°F – 2000°F (1038°C – 1093°C) followed by rapid cooling.
Data are typical, are provided for informational purposes, and should not be construed as maximum or minimum values for specification
or for final design, or for a particular use or application. The data may be revised anytime without notice. We make no representation or
warranty as to its accuracy and assume no duty to update. Actual data on any particular product or material may vary from those shown
herein. TM is trademark of and ® is registered trademark of ATI Properties, Inc. or its affiliated companies. ® The starburst logo is a
registered trademark of ATI Properties, Inc. © 2013 ATI. All rights reserved.
VERSION 1 (6/20/2013): PAGE 5 of 5
Allegheny Technologies Incorporated
1000 Six PPG Place
Pittsburgh, PA 15222-5479 U.S.A.
www.ATImetals.com