Applications Potential

Transcription

1 - PH STAINLESS STEEL P R O D U C T D ATA B U L L E T I N Aerospace Food Processing Petrochemical Paper Metalworking Chemical Applications Potential - PH Stainless Steel is the most widely used of all the precipitation-hardening stainless steels. Its valuable combination of properties gives designers opportunities to add reliability to their products while simplifying fabrication and often reducing costs. This valuable alloy is widely used in the aerospace, chemical, petrochemical, food processing, paper and general metalworking industries. UNS S00 - P H S TA I N L E S S S T E E L

2 TABLE OF CONTENTS Product Description... Composition... Available Forms... Specifications... Standard Heat Treatments... Mechanical Properties... 3 Physical Properties... Dimensional Change... 8 Corrosion Resistance... 9 Formability... 3 Weldability... Heat Treatment... Descaling...

3 PRODUCT DESCRIPTION - PH Stainless Steel is a martensitic precipitation-hardening stainless steel that provides an outstanding combination of high strength, good corrosion resistance, good mechanical properties at temperatures up to 00 F (3 C), good toughness in both base metal and welds, and short-time, low-temperature heat treatments that minimize warpage and scaling. COMPOSITION (wt %) Carbon (C) 0.0 max. Manganese (Mn).00 max. Phosphorus (P) 0.00 max. Sulfur (S) max. Silicon (Si).00 max. Chromium (Cr).00.0 Nickel (Ni) Copper (Cu) Niobium* (Nb) *ASTM A93 requirements call for Niobium plus Tantalum = AK Steel makes no intentional Ta addition. AVAILABLE FORMS AK Steel produces - PH Stainless Steel sheet and strip in thicknesses from in. ( mm). In these forms, the alloy is supplied in Condition A, ready for fabrication and subsequent hardening by the user. Since the material transforms to martensite on cooling to room temperature, flatness requirements should be considered and discussed as part of the order. SPECIFICATIONS The following specifications are listed without revision indications. Contact ASTM Headquarters for latest ASTM revision. For AMS revision, contact AMS Division of SAE. AMS 0 Sheet, Strip and Plate ASTM A93 Plate, Sheet and Strip (Listed as Grade 30 - UNS S00) The values shown in this bulletin were established in U.S. customary units. The metric equivalents may be approximate.

4 STANDARD HEAT TREATMENTS As supplied from the Mill in Condition A, - PH Stainless Steel can be heat treated at a variety of temperatures to develop a wide range of properties. Eight standard heat treatments have been developed. The following chart outlines the times and temperatures required. This alloy exhibits useful mechanical properties in Condition A. Tests conducted at an exposed marine atmosphere on a 80 ft. (. m) lot, 8 ft. ( m) from the waterline, show excellent stress corrosion resistance. Condition A material has been used successfully in numerous applications. The hardness and tensile properties fall within the range of those for Conditions H 00 and H 0. However, in critical applications, the alloy is used in the precipitationhardened condition, rather than Condition A. Heat treating to the hardened condition, especially at the higher end of the temperature range, stress relieves the structure and may provide more reliable resistance to stress corrosion cracking than in Condition A. TABLE STANDARD HEAT TREATMENTS Condition A Solution Treated at 900 F ± F (038 C ± C) or Air cool below 90 F (3 C). Condition Heat To ± F (8. C) Time at, hrs. Type of Cooling H F (8 C) Air H 9 9 F (9 C) Air H 0 0 F ( C) Air H 0 0 F (80 C) Air H F (93 C) Air H 0 0 F ( C) Air H H 0-M 0 F ( C) 0 F ( C) 00 F (0 C) 0 F ( C) followed by followed by Air Air Air Air

5 MECHANICAL PROPERTIES - PH Stainless Steel provides excellent mechanical properties. For applications requiring high strength and hardness plus corrosion resistance, this alloy is an outstanding choice. In addition, it is more cost effective than many high-nickel, non-ferrous alloys. TABLE TYPICAL MECHANICAL PROPERTIES Property Condition A H 900 H 9 H 0 H 0 H 0 H 0-M UTS, 0 (03) 00 (39) 90 (30) 0 () (38) 0 (03) 3 (9) 0.% YS, (93) 8 () (0) (38) 0 (03) 30 (89) () Elongation, % in " (0.8 mm) Rockwell Hardness C TABLE 3 PROPERTIES ACCEPTABLE FOR MATERIAL SPECIFICATION* Property UTS, Condition A H 900 H 9 H 0 H 0 H 00 H 0 8 max. () 0.% YS, 0 max. (03) 90 min. (30) 0 min. () 0 min. () min. (09) min. (09) min. (000) min. (000) min. (8) 0 min. (9) min. (90) 3 min. (93) 0 min. () Elongation, % in " (0.8 mm) 3 min. min. min. min. min. min. 8 min. Rockwell Hardness C 38 max *Sheets and strip. TABLE PIN BEARING PROPERTIES OF SHEET* Condition Bearing Yield Strength** e/d =. e/d =.0 Tensile Strengths*** Bearing Strength Bearing Yield Strength** Bearing Strength 0.% YS UTS H 9 3 (88) 30 (09) 308 () 0 () 90 (30) 9 (3) H 0 (9) 0 (8) 88 (98) 39 () (8) (8) H (0) () (80) 33 (3) 0 (03) 0 (03) H 0 03 (00) 3 (3) 3 () 33 (8) (00) 0 (03) A () (8) (903) 9 (0) 8 (089) 8 (089) *Average of duplicate tests on one heat of 0.0 in. (. mm) sheet material. ** Offset equals % of pin diameter. *** Yield equals ultimate tensile strengths due to rounding. e/d = Distance from edge of specimen to edge of hole + hole diameter. 3

6 ELEVATED TEMPERATURE PROPERTIES Mechanical properties of - PH Stainless Steel Condition H 0 after long-time exposure at elevated temperatures are shown in Table. When tested at room temperature after exposure, a slight loss of toughness and gain in strength can be noted. However, H 0 properties can be restored by heat treating at 0 F ( C) for four hours after original exposure. By taking advantage of this re-aging treatment, the service life of parts exposed at elevated temperature to 0 F (339 C) can be extended indefinitely. Elevated temperature properties for short-time exposures were determined for Conditions H 900 and H 0. Specimens were heated rapidly by resistance methods and reached exposure temperatures within two seconds. Specimens were then held at temperature for the times indicated and tested both at exposure temperature and at room temperature. (See Tables, and 8). TABLE EFFECT OF ELEVATED TEMPERATURE EXPOSURE ON MECHANICAL PROPERTIES CONDITION H 0 Test s Room 00 F (3 C) 0 F (399 C) Prenotched Charpy W/A, in. lb./in. (N/mm ) Exposure F ( C) Time hrs. 00 (3) * 0 (33) * 00 (3) * 0 (399) * UTS (0) (08) (9) (09) 8 (9) (9) (08) () 9 (3) 0 (9) (0) (9) 8 () 0 (9) 0.% (99) 0 (03) 9 (80) 9 (0) () 9 (80) (993) (09) (00) (80) (0) (38) 8 () (80) Elong % in " (0.8 mm) UTS (88) (88) (9) (88) (9) (93) (8) (9) (00) (8) (88) (9) (0) (9) 0.% 8 (8) 3 (88) 0 (38) (8) 3 (93) 08 () 0 (8) 30 (89) (993) 08 () (8) 3 (93) (993) 0 (38) Elong % in " (0.8 mm) 8 UTS (93) 0 (8) 0 (38) (83) 3 (90) 08 () 8 (8) 30 (89) (99) 08 () (83) 3 (93) (993) 0 () 0.% 0 (8) (80) 03 (0) (800) 8 (88) 0 (03) () (8) 3 (9) 03 (0) (93) 9 (889) 38 (9) 0 (9) Elong % in " (0.8 mm) 8 F ( C) 88 (39) 9 (3) 8 (39) 90 (30) (8) (39) 8 (38) 8 (3) (3) 3 (3) 80 (3) 309 (9) 98 (3) 308 (0) - F (-0 C) 0 (3) 3 (89) (39) 08 (33) 9 (9) 398 (0) 93 (3) 80 (3) () 0 (39) 83 (3) 3 () 0 () 30 (0) None None 8 (0) 3 (9) 3 (83) (93) (800) () 08 (3) (3) *Re-aged at 0 F ( C) for hours after exposure.

7 TABLE EFFECT OF SHORT-TIME ELEVATED TEMPERATURE EXPOSURE ON MECHANICAL PROPERTIES CONDITION H 900 TESTED AT ROOM TEMPERATURE Exposure F ( C) Property 000 (38) UTS, 0.% YS, Elong., % in " (0.8 mm) Exposure Time, seconds (9) 9 (38) 0 (88) 89 (303) 0 (88) 93 (33).0 0 (8) 9 (338).0 0 (3) 8 (90) 0 () 9 (3). 0 (38) 88 (9).0 00 (93) UTS, 0.% YS, Elong., % in " (0.8 mm) 0 (38) 83 (). 0 (0) 8 (9) 8. 9 (39) 8 (8).0 9 (3) (0) 9 (3) 80 (). () 0 ().0 8 (8) () 00 (9) UTS, 0.% YS, Elong., % in " (0.8 mm) 8 (90) 3 (93) 8 (90) (8) 9 (3) ().0 8 (8) 8 (9) (38) 3 (). (3) 9 (0) 3 () 8 (00) 300 (0) UTS, 0.% YS, Elong., % in " (0.8 mm) (8) (00) 9.0 (8) (0) (38) 3 (9) () 3 (98) 0 (03) 3 (9). (09) ().0 (0) 3 (903).0 00 (0) UTS, 0.% YS, Elong., % in " (0.8 mm) (38) 3 (90) 8. (3) 3 (88) (0) (8).0 () 0 (8) 9 (09) (8) 0 (03) (8).0 (08) 8 (8) 00 (8) UTS, 0.% YS, Elong., % in " (0.8 mm) ( ) (83) (38) (83).0 (38) (8).0 (38) (83).0 (00) (89). () 8 (88). 800 (98) UTS, 0.% YS, Elong., % in " (0.8 mm) (0) 9 (80) 9 (09) 9 (80) 8 (089) (8). (08) 8 (8) 000 (093) UTS, 0.% YS, Elong., % in " (0.8 mm) (0) (8) (0) (800).0 8 (089) 09 ().0 Control Sample: UTS. 9 ksi. (89 MPa) 0.% YS 9 ksi. (3 MPa) Elong., % in " (0.8 mm) 8. TABLE EFFECT OF SHORT-TIME EXPOSURE AT 00 F (0 C) ON MECHANICAL PROPERTIES CONDITION H 0 Test F ( C) Property Room UTS, 0.% YS, Elong., % in " (0.8 mm) Exposure Time, seconds (0) 30 (89).0 (0) (8) 9.0 (0) (8) (0) (93) (03) () 8. 0 (03) (80) (0) 0 () 00 (0) UTS, 0.% YS, Elong., % in " (0.8 mm) (3). (3).0 3. (9). (93) 9.0. (3) (3).0. (3). (38) (33).3 (3). (30) 3. (98) (30).3 (9).0 Control Sample: UTS ksi. (08 MPa) 0.% YS 3 ksi. (98 MPa) Elong., % in " (0.8 mm).0

8 TABLE 8 EFFECT OF ELEVATED TEMPERATURE EXPOSURE FOR 30 SECONDS ON MECHANICAL PROPERTIES CONDITION H 0 Test F ( C) Property Room UTS, 0.% YS, Elong., % in " (0.8 mm) Exposure, F ( C) 000 (38) 00 (9) 00 (0) 00 (8) 800 (98) 000 (093) (09) (9) 0.0 (0) 3 (938).0 (0) (8) 9.0 (09) (80). (09) 08 () (08) 3 (9). Exposure UTS, 0.% YS, Elong., % in " (0.8 mm) 8 (88) 08 (). (8). (93) 3.0. (3) (3).0 3 () 3. (8). (83). (9). (03). (8) Control Sample: UTS ksi. (08 MPa) 0.% YS 3 ksi. (98 MPa) Elong., % in " (0.8 mm).0 FIGURE EFFECT OF 30 SECOND ELEVATED TEMPERATURE EXPOSURE ON ROOM TEMPERATURE PROPERTIES Ultimate Tensile Strength (MPa) Ultimate Tensile Strength (ksi.) H 0 H Exposure, ( F) Exposure, ( C) NOTE: These tests represent instant heating of the entire cross section of the test specimens. Under actual conditions, heating rates would depend on heat source, surface conditions and thermal conductivity of AK Steel - PH Stainless Steel (see Physical Properties). Times and temperatures shown in the tables apply only after parts have reached temperatures.

9 PHYSICAL PROPERTIES TABLE 9 PHYSICAL PROPERTIES A (Magnetic) H 900 (Magnetic) Condition H 0 (Magnetic) H 0 (Magnetic) Density, lbs./in. 3 (g/cm 3 ) 0.8 (.8) 0.8 (.80) 0.83 (.8) 0.8 (.8) Electrical Resistivity, µω cm 98 Specific Heat, BTU/lbs./ F (kj/kg/k) 3 - F (0-00 C) 0. (0.) 0. (0.) Thermal Conductivity BTU/hr./ft. / F (W/m/K) 300 F (9 C) 00 F (0 C) 80 F (0 C) 900 F (8 C) Mean Coefficient of Thermal Expansion in./in./ F (μm/m/k) F (-3 C) 0 00 F ( 93 C) 0 00 F ( 0 C) 0 00 F ( 3 C) F ( C) F ( 8 C) x 0 - (0.8) x 0 - (0.8). x 0 - (.).3 x 0 - (.3) (.9) 3 (9.) (.) (.).8 x 0 - (0.) x 0 - (0.8) x 0 - (0.8).3 x 0 - (.3). x 0 - (.) Modulus of Elasticity, 8. x 0 (9 x 0 3 ).3 x 0 - (.3). x 0 - (.). x 0 - (.9).8 x 0 - (.). x 0 - (.0). x 0 - (.9).9 x 0 - (.). x 0 - (.8). x 0 - (3.0).3 x 0 - (3.) Modulus of Rigidity, in Torsion, 9.8 x 0 3 ( x 0 3 ).00 x 0 3 ( x 0 3 ) 0.0 x 0 3 (0 x 0 3 ) Poisson's Ratio (all conditions) 0.

10 DIMENSIONAL CHANGE DIMENSIONAL CHANGE IN HARDENING As indicated by the density values, - PH Stainless Steel undergoes a volume contraction when it is hardened. This produces a predictable change in dimensions that must be taken into consideration if parts made of this alloy must be manufactured to close tolerances. TABLE 0 CONTRACTION FROM HEAT TREATMENT Condition H 900 H 9 H 0 H 00 H 0 H 0-M Contraction in./in. (mm/mm) > > >0.003 *Data represent single tests from one heat. FIGURE DIMENSIONAL CHANGE IN HARDENING HELD AT 900 F (038 C) FOR / HOUR AC = 0 F ( C) AC 3 = 300 F (0 C) Dilatation 0.% HEATING HEATING COOLING HELD AT 900 F (8 C) FOR HOUR COOLING M f INITIAL CONDITION ANNEALED M s = 0 F (3 C) , ( F) , ( C)

11 CORROSION RESISTANCE CORROSION RESISTANCE - PH Stainless Steel provides excellent corrosion resistance. It withstands corrosive attack better than any of the standard hardenable stainless steels and is comparable to Type 30 in most media. This has been confirmed by actual service in a wide variety of corrosive conditions in the petrochemical, petroleum, paper, dairy and food processing industries, and in applications such as boat shafting. Additional proof of its durability is the replacement of chromium-nickel stainless steels and high-alloy non-ferrous metals by this alloy for a broad range of parts requiring excellent resistance to corrosion. LABORATORY TESTS Hundreds of laboratory corrosion tests have been conducted on - PH Stainless Steel to provide data for comparison with other stainless steels. As chemically pure reagents were used, the data are useful as a guide to the comparative ranking of this alloy with the other materials, but are not a measure of their performance under actual operating conditions. Typical corrosion rates for the material in a variety of media are listed in Table along with comparable data for Type 30. In general, the corrosion resistance of - PH Stainless Steel is similar to Type 30 in the media tested, depending on heat-treated conditions. For specific applications, see the details of Table or conduct pilot corrosive tests. ATMOSPHERIC EXPOSURE In rural and mild industrial atmospheres, - PH Stainless Steel has excellent resistance to general corrosion in all heat-treated conditions. It is equivalent to Type 30 stainless steel in these environments. The alloy exposed to seacoast atmosphere will gradually develop overall light rusting and pitting in all heat-treated conditions. It is almost equal to Type 30 and much better than the standard hardenable stainless steels in this environment. SEAWATER EXPOSURE The combination of high mechanical strength and good corrosion resistance makes this alloy well suited for many marine applications such as valve and pump parts. However, in common with other stainless steels, the material is subject to crevice attack if exposed to stagnant seawater for any length of time. If equipment exposed to seawater is not operated continuously, cathodic protection is highly desirable to prevent such attack. 9

12 TABLE CORROSION RATES OF AK STEEL - PH IN VARIOUS CHEMICAL MEDIA Chemical Medium Concentration % H SO HCI 0. HNO 3 0 Formic Acid 0 Acetic Acid 33 0 H 3 PO NaOH Temp. C Corrosion Rate, mils per year (a) AK Steel - PH SS (b) Type 30 (b) H 9 H 0 H 0 H 0 Annealed Boiling Boiling Boiling 80 Boiling () () () () Ammonium Hydroxide 0 Boiling 0% HNO 3 % HF % HNO 3 3% HF Cola Soft Drink Syrup Concentrated 3 Salt-Sugar-Vinegar Boiling (a) Rates were determined by total immersion of 0. in. (.8 mm) diameter x 0. in. (.8 mm) long cylindrical test specimens for five 8-hour periods. Specimens were electrolytically activated for the last three periods except for the boiling percent nitric acid test and also for Type 30 bar in boiling sodium hydroxide. For Type 30 bar, passive periods were not averaged. In most cases, where rates of replicates varied, the highest is given. Other exceptions to all of foregoing are marked. (b) Numbers in parentheses indicate the number of periods in testing. - indicates rates of less than mil/year. (c) Rates increase from period to period. Rate is average of periods. Data Reference: J. J. Halbig & O. B. Ellis, Observations on Corrosion Resistance of High Strength Stainless Steels for Aircraft, Corrosion, Vol., pp. 389t-39t (98) (c) (c) 3 (c) 8 () 80 () 0

13 STRESS CORROSION CRACKING Stress corrosion cracking, although occurring infrequently, can be a source of failure in stainless steels. It usually takes place in highly stressed parts that are exposed under conditions that permit local concentration of chlorides. Tests using smooth bent beam specimens stressed up to the 0.% yield strength of the material and exposed to marine atmosphere on the 80 ft. (. m) lot, 8 ft. ( m) from the waterline, show that - PH Stainless Steel is quite susceptible to stress corrosion cracking when in Condition H 900. In Condition A, and when hardened at temperatures of 0 F ( C) and higher; the alloy is highly resistant to stress corrosion cracking. In addition, many years of service experience in marine atmospheres and in high-purity water at high temperatures demonstrate the resistance of the alloy to this type of failure. For maximum resistance to chloride stress corrosion cracking, the alloy should be hardened at the highest aging temperature that will yield required properties, but not less than 0 F ( C). Another set of smooth bent beam specimens involving welded - PH Stainless Steel in Conditions H 900, H 0, H 0 and H 0 were stressed at 90% of the 0.% yield strength of the material and exposed to a marine atmosphere on the 80-foot lot at Kure Beach, North Carolina. The samples were divided into three groups:. Not Welded (Solution Treated + Aged). Solution Treated + Welded + Aged 3. Welded + Solution Treated + Aged All specimens in Condition H 900 failed in 8 days or less, regardless of whether welded or not. None of the other specimens failed after more than years in test. In addition, welded specimens were made by fusing in. (0.8 mm) diameter circular weld beads onto one face of / in. (.3 mm) thick - PH Stainless Steel plate. After welding and final heat treatment, the surfaces were ground to a smooth finish. The internal stresses caused by welding are very high and can equal or exceed the yield strength of the material. These specimens were exposed to quiet seawater at Wrightsville Beach, North Carolina. The welding and heat-treating conditions were as follows:. Solution Treated + Aged to Conditions H 0, H 0, H 0 + Welded.. Welded + Solution Treated + Aged to Conditions H 0, H 0, H Solution Treated + Welded + Aged to Conditions H 0, H 0, H 00. Careful examination showed there was no evidence of stress corrosion cracking in any of the test specimens after one year in test. TABLE STRESS CORROSION CRACKING* Condition Applied Stress, Time to Failure** A (Heat ) 93 H 900 (Heat ) 8 0 H 9 (Heat ) 3 30 H 9 (Heat ) 8 H 0 (Heat ) 0 H 0 (Heat ) 3 3 H 0 (Heat ) 0 8 (8) 00% YS () % YS (89) 00% YS (9) % YS (93) 00% YS (89) % YS (8) 00% YS (89) % YS (9) 90% YS (800) % YS (93) 90% YS (9) % YS (03) 90% YS (8) % YS 3NF 3NF - days, -3 days - days, -8 days, -3 days - months, -39 months, NF -3 months, - months, NF 3NF -8 months, NF NF NF NF NF NF NF *Smooth bent beam strip specimens were exposed on the 80 ft. (. m) lot, 8 ft. ( m) from the waterline. Five replicates of in. (.3 mm) thick strip from Heat were exposed. Samples of 0.0 in. (. mm) thick strip from Heat were exposed in triplicate in each heat-treated condition. **NF indicates No Failure as of September 98.

14 HYDROGEN EMBRITTLEMENT Hydrogen embrittlement is a potential threat to all high strength martensitic steels wherever the reduction of hydrogen ions to atomic hydrogen may occur. Commonplace examples are aqueous corrosion, cathodic protection to prevent corrosion, galvanic coupling with less noble metals and electroplating. When exposed to 8% HCl-% SeO solution and stressed to 00,000 ksi. (90 MPa) in direct tension, - PH Stainless Steel aged at temperatures ranging from F (8 C) failed from hydrogen embrittlement within four hours. Aging at temperatures above 00 F (93 C) conferred immunity to cracking, while at 00 F (93 C) a borderline situation existed, with material sometimes resistant to cracking and sometimes not. Despite the susceptibility of - PH Stainless Steel to hydrogen embrittlement that is shown by this severe test, only a few isolated instances of its failure in service by this mechanism have been recorded. Apparently, under nearly all conditions of use, this alloy possesses adequate resistance to hydrogen embrittlement. Where this problem is acute and strength requirements permit, the alloy should be aged at temperatures of 00 F (93 C) or higher to ensure freedom from cracking. SULFIDE STRESS CRACKING Laboratory tests run in synthetic sour well solution (% sodium chloride + /% acetic acid saturated with hydrogen sulfide) in accordance with NACE Test Method TM-0- show that, for best resistance to this aggressive medium, the alloy should either be in Condition H 0-M or aged at 0 F (0 C) for two -hour periods. In either of these heat-treated conditions, - PH Stainless Steel is considered by NACE as acceptable for use in sour (sulfide) service and is included in MR-0-.

15 FORMABILITY FORMABILITY Because - PH Stainless Steel in Condition A is hard, forming normally should be limited to mild operations. However, formability can be greatly improved by heat treating before cold working or by use of hot-forming methods. OVERAGING FOR COLD FORMING Aging by various heat treatments can be used to improve formability in certain operations such as stretch forming. This is indicated by the percent elongation values reported in Table. It should be noted, however, in Table 3, that Olsen cup values (used as a relative comparison of drawability) did not show any improvement in overaged samples. TABLE 3 PROPERTIES AND FORMABILITY OF - PH STAINLESS STEEL AT ROOM TEMPERATURE* Condition 0.% YS UTS Elongation % in " (0.8 mm) Rockwell Hardness C Olsen Cup Draw in. (mm) A 0.0 (8). (08) (0.838) H 900 ( hour) 8. (8) 00. (380) (0.3) H 0 ( hours) 3.8 (9). (99) (0.838) Aged at 300 F (0 C) hours 03. (). (983) (0.30) Aged at 00 F (0 C) hours.0 (80) 8. (0) (0.8) H 0-M 08. (8) 3.0 (903) (0.830) *Average of duplicate tests. The mechanical properties in Table 3 can be used as a guide in selecting the type of cold forming operation to be used for various conditions. In biaxial operations, such as drawing, Condition A may be just as satisfactory as an overaged condition. However, for stretch forming and similar operations, test data indicate an overaged condition such as H 0 or H 0-M is preferred. It should be recognized, also, that when parts are cold formed in an overaged condition, they must be re-solution treated at 900 F (038 C) after forming, and prior to aging to any of the higher strength conditions such as H 900 if the high strength developed by such a heat treatment is needed. If extremely high strength is not needed, - PH Stainless Steel still offers attractive properties as formed in Condition H 0 or H 0-M. Yield strength, for example, would be more than twice that obtained in an austenitic grade such as Type 30. However, when severe forming is done in an overaged condition, it is recommended that the formed part be re-aged to relieve residual stresses and restore toughness. 3

16 BEND PROPERTIES Table is a summary of bend test data from tests conducted on flat sheets and strip ranging in thickness from in. (0.38. mm). TABLE BEND TEST DATA MINIMUM BEND RADIUS* Condition L T L T L T A 3T T 3T T T 9T H 900 3T T 3T T T 9T H 9 T T 3T T T 9T H 0 T T 3T T T T H 0 T T 3T T T T H 0 T T T 3T T T *Expressed as function of sheet thickness. Minimum radius to make indicated bend with no fissuring when viewed under 0X magnifying glass. HOT FORMING As indicated by the high elongation shown in Table, - PH Stainless Steel can be formed quite readily by first solution treating (austenitizing) at 900 F (038 C), then forming during cooling from this temperature while the steel is still austenitic. The preferred temperature range for such forming is at F (33 8 C), which is well above the M s temperature of the steel (M s approximately 0 F (3 C)). Mechanical properties of hot-formed parts subsequently hardened are not significantly different from those obtained by standard heat treatments. TABLE MECHANICAL PROPERTIES OF AK STEEL - PH Heated to 900 F (038 C) Tests at During Cool Down Test F ( C) 00 (0) 00 (0) 0 (88) 00 (3) 0 (33) 00 (3) 0 (339) 800 () 900 (8) 0.% YS 0. (39) 3.0 (9). (). (3). (). ().9 (). (9). () UTS 3. (990). (8).8 (8).0 (8) 0 () 0. (98) 8. (00) 9. (9) 3.0 (3) Elongation % in (0.8 mm) Rockwell Hardness C Cooled to RT Aged at 900 F (8 C) 3 3 3

17 TABLE ROOM TEMPERATURE PROPERTIES OF - PH STAINLESS STEEL Stretched on Cooling from Solution Treatment Hot Forming Test Temp. F ( C) 00 (0) 0 (33) 0 (33) 0 (33) 0 (33) 0 (33) 800 () 800 () 800 () Standard H 900 % Stretch in " (0.8 mm) Aging ( hrs) F ( C) 900 (8) 900 (8) 900 (8) None 900 (8) 00 () 900 (8) None 900 (8) 0.% YS (3) () (8) (9) (8) (09) () (800) () (9) UTS (339) (3) (33) () (338) (03) (3) (03) (30) (3) Elongation % in " (0.8 mm) Olsen cup values for - PH Stainless Steel are given in Table at room temperature as well as hot forming temperatures. Also included for comparison are properties for - PH Stainless Steel in Condition A (a readily formed precipitation-hardening stainless steel developed by AK Steel). The benefits of hot forming - PH Stainless Steel are quite apparent. TABLE OLSEN CUP DRAW TESTS ON - PH AND - PH STAINLESS STEELS AT ROOM AND ELEVATED TEMPERATURES Grade Condition - PH - PH - PH - PH Aged at 00 F (9 C) A A A Thickness in. (mm) (0.0) (0.0) (0.0) (0.0) Test RT RT Hot* RT Depth of Olsen Cup Draw in. (mm) 0.0 (.) (..) ( ) (8.9 9.) *Solution treated at 900 F (038 C), then transferred hot to Olsen machine for cup test. Strip temperature at start of test approximately 000 F (38 C).

18 WELDABILITY The precipitation hardening class of stainless steels is generally considered to be weldable by the common fusion and resistance techniques. Special consideration is required to achieve optimum mechanical properties by considering the best heat-treated conditions in which to weld and which heat treatments should follow welding. This particular alloy is the most common member of the class and is generally considered to have the best weldability. When a weld filler is needed, AWS E/ER 30 is most often specified. - PH Stainless Steel is well known in reference literature and more information can be obtained in the following ways:. ANSI/AWS A.9, A., and A. (stainless steel filler metals, welding electrode specifications).. Welding of Stainless Steels and Other Joining Methods, SSINA ( HEAT TREATMENT For maximum hardness and strength, material in the solution-treated condition is heated for one hour at 900 F ± F (8 C ± 8. C) and air cooled to room temperature. If the material is purchased in the solution-treated condition (Condition A) and not subsequentlyhot worked, the hardening treatment can be performed without solution treating before hardening. Where ductility in the hardened condition is of importance, better toughness can be obtained by raising the temperature of the hardening heat treatment. Unlike regular hardenable materials that require hardening plus a tempering or stress relieving treatment, this alloy can be hardened to the final desired properties in one operation. By varying the heat-treating procedure between F (8 C) for one to four hours, a wide range of properties can be attained. If the alloy is not sufficiently ductile in any given hardened condition, it can be reheated at a higher hardening temperature to increase impact strength and elongation. This can be accomplished without a solution treatment prior to final heat treatment. However, strength will be reduced. For hot-worked or overaged material, a solution treatment at 8 9 F (0 0 C) for three minutes for each 0. in. (. mm) of thickness, followed by cooling to at least 90 F (3 C) must be done prior to hardening. The solution treatment refines the grain sizeand makes hardened material more uniform. When fabricating - PH Stainless Steel, it is important to keep in mind the low temperatures at which the start of transformation to martensite (M s) and the completion of the martensite transformation (M f) occur. These temperatures are approximately 0 F (3 C) and 90 F (3 C) respectively. Because of this characteristic, it is necessary to cool parts in process at least to 90 F (3 C) prior to applying subsequent heat treatments if normal final properties are to be obtained. This practice is essential to assure grain refinement and to assure good ductility.

19 DESCALING Hardening treatments produce only a light heat tint on surfaces. This tint can be removed easily by mechanical means such as wet grit blasting or with a short pickle in 0% nitric % hydrofluoric acid (by volume) at 0 0 F (3 0 C). Where pickling is undesirable, heat tint may be removed by a light electropolishing operation. The latter two treatments also clean and passivate the surfaces for maximum corrosion resistance. Where solution treating is performed, the following pickling method satisfactorily removes surface scale. The use of molten salts such as sodium hydride or Kolene processes to descale is limited since these methods partially harden solution-treated material. Procedure Acid Bath Step Caustic Permanganate Step 0% Nitric Acid + % Hydrofluoric Acid F ( C) Time at Minutes 0 80 ( 8) 0 Water Rinse 0 0 (3 0) 3 Hot water, high pressure water or brush scrub In pickling operations, close control of time and temperature is necessary to obtain uniform scale removal without over-etching. Scale softening methods may be used on material that has been solution treated (not pickled) and precipitation hardened.

20 AK Steel Corporation 9 Centre Pointe Drive West Chester, OH 09 8.STEEL sales@aksteel.com AK Steel is a leading producer of flat-rolled carbon, stainless and electrical steel products, and carbon and stainless tubular products, primarily for automotive, infrastructure and manufacturing, construction and electrical power generation and distribution markets. Headquartered in West Chester, Ohio (Greater Cincinnati), the company employs approximately 8,00 men and women at eight steel plants, two coke plants and two tube manufacturing plants across six states (Indiana, Kentucky, Michigan, Ohio, Pennsylvania and West Virginia) and one tube plant in Mexico. Additional information about AK Steel is available at The information and data in this document are accurate to the best of our knowledge and belief, but are intended for general information only. Applications suggested for the materials are described only to help readers make their own evaluations and decisions, and are neither guarantees nor to be construed as express or implied warranties of suitability for these or other applications. Data referring to material properties are the result of tests performed on specimens obtained from specific locations of the products in accordance with prescribed sampling procedures; any warranty thereof is limited to the values obtained at such locations and by such procedures. There is no warranty with respect to values of the materials at other locations. AK and the AK Steel logo are registered trademarks of the AK Steel Corporation..3.