CHROMESHIELD 22 STAINLESS STEEL

Transcription

1 CHROMESHIELD 22 STAINLESS STEEL R E L I M I N A RY R O D C T D ATA B L L E T I N Appliances Food Service Equipment Architectural Welded Components Tubing Cookware Applications otential CHROMESHIELD 22 Stainless Steel combines the exceptional corrosion performance of a high chromium ferritic alloy with the enhanced ductility of AK Steel s LTRA FORM technology. CHROMESHIELD 22 Stainless Steel is dual stabilized with both titanium and niobium (columbium) to improve weld corrosion performance. Small additions of copper and molybdenum further enhance corrosion resistance. CHROMESHIELD 22 Stainless Steel is more corrosion resistant than Type 430, Type 441 and even in some environments. CHROMESHIELD 22 Stainless Steel is acceptable for the food contact zone of restaurant equipment under NSF International Standard 51. C H R O M E S H I E L D 2 2 S TA I N L E S S S T E E L

2 TABLE OF CONTENTS roduct Description... 1 Composition... 1 Available Forms... 1 hysical roperties... 2 Mechanical roperties... 3 Corrosion Resistance... 4 Oxidation Resistance... 6 Weldability... 6

3 RODCT DESCRITION CHROMESHIELD 22 Stainless Steel is a high chromium ferritic stainless steel with small copper and molybdenum additions that further enhance the corrosion resistance. The grade is dual stabilized with both titanium and columbium to improve weld corrosion performance. CHROMESHIELD 22 Stainless Steel is more corrosion resistant than Type 430, Type 441 and even in some environments. COMOSITION (wt %) Carbon (C) 0.02 max. Manganese (Mg) 1.00 max. hosphorus () 0.03 max. Sulfur (S) 0.01 max. Silicon (Si) 1.00 max. Chromium (Cr) Nickel (Ni) 0.40 max. Molybdenum (Mo) Copper (Cu) Titanium + Niobium (Ti + Nb) AVAILABLE FORMS (C+N) min. CHROMESHIELD 22 is available in most gauges, in widths up to and including 48 in. and is available in 2D, 2B, and directional polished finishes. TABLE 1 TYICAL ROOM TEMERATRE MECHANICAL ROERTIES TS ksi. (Ma) 0.2% YS ksi. (Ma) Elongation % in 2" (50.8 mm) Rockwell Hardness 76 (524) 56 (386) 31 B84 MICROSTRCTRE CHROMESHIELD 22 Stainless Steel features a uniform equiaxed grain structure that enhances material formability. TABLE 2 FORMABILITY lastic Strain Ratio * Olson Cup Height r Ridge Rating m r 1 r 2 in. (mm) (11.2) * Δr 1 = (r 0 +r 90-2r 45 )/2; Δr 2 = r max. -r min. Rating scale of 1 5 with 5 the heaviest. Typical microstructure at 100X original magnification as etched with Vilella's etchant. 1

4 HYSICAL ROERTIES TABLE 3 SECIFIC HEAT AND THERMAL CONDCTIVITY Temperature C ( F) Specific Heat Thermal Conductivity J/g/K W/m/K (BT/hr./ft./ F) 23 (73.4) (122) (212) (392) (572) (752) (932) (1112) (1292) (1472) (1652) (1832) CET, 10-6 / C FIGRE 1 MEAN COEFFICIENT OF THERMAL EXANSION TABLE 4 ELECTRICAL RESISTIVITY Temperature C ( F) Temperature, C Heating µm cm Cooling 23 (73) (122) (212) (392) (572) (752) (932) (1112) (1292) (1472) (1652) (1832)

5 MECHANICAL ROERTIES HIGH TEMERATRE CREE RESISTANCE Sag resistance testing is a simple, common measure of a materials resistance to creep. In testing the sag resistance of CHROMESHIELD 22 Stainless Steel was found to be superior to Type 439 and equivalent to Type 444. TABLE 5 DEFLECTION AFTER 100 HOR TEST DRATION 1600 F (871 C) TEST TEMERATRE Alloy Deflection* in. x 10-3 (mm) 101 (2.57) Type (6.12) Type (2.54) 18 Cr-Cb SS 89 (2.26) * Average of triplicate tests. TABLE 6 CHARY V-NOTCH IMACT TOGHNESS Temperature F ( C) Hot Rolled * in. lbs./in. 2 (J/cm 2 ) Cold Rolled & Annealed in. lbs./in. 2 (J/cm 2 ) Welded (Autogenous GTAW) in. lbs./in. 2 (J/cm 2 ) 72 (22) 4151 (72.69) 8378 (146.7) (206.3) 32 (0) 4655 (81.52) 8317 (145.6) (210.7) 0 (-17) 2385 (41.76) 7975 (139.6) 8993 (157.5) -20 (-28) 2308 (40.41) -30 (-34) 6868 (120.2) 6568 (115.0) -40 (-40) 1480 (25.91) -60 (-51) 7057 (123.5) 507 (8.87) * Gauge = in. (4.57 mm) Gauge = in. (191 mm) FIGRE 2 EFFECT OF COLD REDCTION ON MECHANICAL ROERTIES FIGRE 3 TYICAL ELEVATED TEMERATRE STRENGTH ROERTIES Strength, Ma % YS TS Elongation Elongation % in 2" (50.8 mm) Strength, Ma % YS TS % Cold Reduction Temperature, C 3

6 CORROSION RESISTANCE AK Steel CHROMESHIELD 22 Stainless Steel exhibits superior chloride pitting resistance when compared to Type 430 and Type 441 Stainless Steels. The nickel free 22% Cr plus Cu, low Mo alloy has an overall chloride resistance that is the same if not better than that shown by stainless steel. The dual stabilized ferritic shows excellent intergranular corrosion resistance when welded and is not prone to the chloride stress corrosion cracking that austenitic grades tend to suffer. CHROMESHIELD 22 Stainless Steel resists staining from common food products and has comparable resistance to various cleaners and bleaching agents as. FIGRE 4 CHLORIDE ITTING RESISTANCE Electrochemical Breakdown otential in 3.5% sodium chloride solution at room temperature. 850 Breakdown otential, mv More Resistance to itting 250 Type 430 Cycle Repeats 3 times per day CCT 1 CYCLE CORROSION TEST Salt application Four hours 5% salt spray at 95 F (35 C) Dry cycle Two hour dry cycle at 140 F (60 C) <30% RH Wet cycle Two hour wet cycle at 120 F (50 C) <95% RH CCT 1 CORROSION TEST Cyclic corrosion testing per CCT 1 test procedure after 50 cycles of exposure. Type 430 4

7 CHROMESHIELD 22 STAINLESS STEEL CORROSION RESISTANCE artial immersion for 120 hr. in Household Bleach at 50 C TABLE 7 STAINING RESISTANCE roduct Type 430 Ketchup No Attack Mustard No Attack Hot Sauce No Attack Lemon Juice No Attack Tomato Sauce Horseradish Sauce niform Attack itting Attack TABLE 8 CHLORIDE STRESS CORROSION CRACKING RESISTANCE ASTM G123 Boiling 25% Acidified Sodium Chloride Material Time To Failure 336 hours assed 1000 hours with no cracking TABLE 9 INTERGRANLAR CORROSION TEST OF WELDS ASTM A262/A763 Material Copper-Copper Sulfate Oxalic Etch Type 430 Fail Fail Ditch ass* ass* Step ass* ass Step * Low carbon variety only Type X photomicrographs after Oxalic Acid screening following ASTM A262/A763 5

8 OXIDATION RESISTANCE CHROMESHIELD 22 has improved resistance to cyclic oxidation than the 17-18% chromium bearing alloys and superior performance when compared to Type 409. At 1650 F (899 C), this 22% chromium, low molybdenum ferritic alloy shows to have cyclic oxidation resistance comparable to the 2% molybdenum bearing Type 444. FIGRE 5 CYCLE OXIDATION AT 1650 F (900 C) Mass Change, mg/in Type 409 Type Cr-Cb SS Type 444 CHROMESHIELD 22 SS Number of Cycles WELDABILITY Testing has shown that the CHROMESHIELD 22 Stainless Steel product is readily weldable by the gas tungsten arc (GTAW), Laser (LBW), and resistance spot welding (RSW) processes. Special consideration is required to avoid brittle fractures in the weld zone during fabrication. Maintaining low weld heat input, minimizing discontinuities, and occasionally warming the part somewhat before forming may be helpful. This particular alloy is generally considered to have somewhat poorer weldability when compared to the most common alloy of the stainless class, Type 409. When a weld filler is required, AWS ER308L or ER2209 may be considered. TABLE 10 WELDED* ROOM TEMERATRE MECHANICAL ROERTIES TS ksi. (Ma) 0.2% YS ksi. (Ma) Elongation % in 2" (50.8 mm) Olsen Cup Height in. (mm) Minimum 180 Bend Radius 75 (517) 55 (379) (11.2) OT * Autogenous GTAW 6

9 AK Steel Corporation 9227 Centre ointe Drive West Chester, OH STEEL AK Steel is a world leader in the production of flat-rolled carbon, stainless and electrical steel 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 8,000 men and women at eight steel plants, two coke plants and two tube manufacturing plants across six states: Indiana, Kentucky, Michigan, Ohio, ennsylvania and West Virginia. 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