Oxidation Resistance of 316 1.4401 316L 1.4404 Stainless Steel

The Alloys 316 and 317L exhibit excellent resistance to oxidation and a low rate of scaling in air atmospheres at temperature up to 1600 to 1650°F (871 to 899°C). The performance of Alloy 316 is generally somewhat inferior to that of Alloy 304 stainless steel tube which has slightly higher chromium content (18% vs. 16% for Alloy 316). Since the rate of oxidation is greatly influenced by the atmosphere encountered and by operating conditions, no actual data can be presented which are applicable to all service conditions.

perature range between (700-900)C° in (air and H2O) for 120h at 10 h cycle. The oxidation kinetics for uncoated St.St.316L in air environment are found to be linear, while the oxidation kinetics at water vapor environment are found to be nearly parabolic. The linear rate constant (KL) and the parabolic rate constant (Kp) values obtained at 800C° in air and water vapor are –2.77*10 -7 (mg/cm 2 )/s and 2.18*10 -5 (mg 2 /cm 4 )/s respectively. The phases present on the cyclic oxidation of uncoated St.St.316L surface under most test conditions as revealed by XRD analysis are chromium (III) oxide, NiFe2O4, NiCr2O4 and iron oxide. Oxide phases that were formed on coated systems during air and H2O oxidation exposure condition are FeAl2O4, Fe(Al,Cr)2O4 and Fe2O3. The oxidation kinetics for both coated systems in air and water vapor are found to be linear and parabolic respectively.

The cyclic oxidation resistance of austenitic stainless steel (AISI 316L) can be improved by enriching the surface composition in Al and Si using pack cementation process. In this work, stainless steel is coated with two different types of coatings, the first one is Si-modified aluminide coating and the second is the Ce-doped silicon modified aluminide coating. Aluminum, silicon with and without cerium were simultaneously deposited by diffusion into St.St.316L substrate by the packcementation process, using a pack mixture containing (18%A1, 7%Si, 2%NH4C1 and 73%Al2O3) and 0.5% Ce (wt %) when required.

Cyclic oxidation at high temperature and at different environments of air and water vapor (H2O) were conducted in order to study the thermal shock and oxidation resistance of austenitic stainless steel (316L) with and without siliconmodified aluminide diffusion coating and with cerium doped silicon-modified aluminide diffusion coating.

During cyclic oxidation, the furnace temperature was controlled within ±3C° by using Ni-chrome thermocouple type K. The thermocouple was inserted into the furnace chamber through an access hole on the tope of the furnace and positioned in the proximity of the samples. The thermocouple was calibrated at three standard temperatures of boiling water, tin melting point, and aluminum melting point. The evaluation of the oxidation resistance of the coatings has been carried out by heating the samples in a furnace at test temperature and weighing them every 10 h. the samples were removed from the furnace, allowed to cool, ultrasonically cleaned in ethanol to detach the spalled oxide and the weight change per unit surface area was determined according to Martinengo et al procedure.

Oxidation in Dry Air

Austenitic stainless steel tubes (316L) with and without silicon-modified aluminide diffusion coating , and with cerium doped silicon-modified aluminide diffusion coating samples were accurately weighed and then placed into ceramic crucibles . Cyclic oxidation tests were carried out in a Carbolite programmable furnace (manufactured by Sheffield, England) in the temperature range 700C°-900C° in air at 1 atmospheric pressure. Each heating cycle includes heating in the furnace for 10 hours at the test temperature and cooling in still air. Samples weights changes before and after each oxidation cycle were measured. Normally, at least 3 weight measurements were taken.

Oxidation in Water Vapor

The cyclic Oxidation tests were conducted in water vapor in the temperatures range (700C°-900C)± 5C° and the samples of St.St.316L with and without silicon-modified aluminide diffusion coating, and with cerium doped silicon-modified aluminide diffusion coating. The tube furnace has a water vapor inlet, which permits a preheated vapor at test temperature before it makes contact with the samples. The reaction chamber was first heated to 200C° in air. Water vapor generated in an evaporator was introduced thereafter. The chamber was pumped with water vapor, the chamber was heated up to the desired temperature. After each oxidation cycle was allowed to cool to room temperature for interrupted weightmeasurements after each cycle of 10h up to 120h of cumulative exposure at the respective test temperature.

SA 213 TP 316L

Oxidation Resistance of Stainless Steel
Oxidation Behavior of Type 321 Stainless Steel Tube
310S Elevated Temperature Oxidation Resistance
316L Oxidation Resistance
317L Oxidation Resistance
321 Elevated Temperature Oxidation Resistance
347 Elevated Temperature Oxidation Resistance
410S Oxidation Resistance