Potential for Application of Special Stainless Steels for Chemical Process Equipments

2013 ◽  
Vol 794 ◽  
pp. 691-696
Author(s):  
K. Elaya Perumal
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Case Studies ◽  
Stainless Steels ◽  
Chemical Process ◽  
Elevated Temperatures ◽  
Austenitic Stainless Steels ◽  
Process Conditions ◽  
Petrochemical Plant ◽  
Uniform Corrosion

The most predominant material of construction (MOC) for process equipments in chemical process industries (CPI) is plain carbon steel only. This is because of its lowest cost, easy availability, adequate thermal and mechanical properties, ease of fabrication etc. The only limitation is its low corrosion resistance. When corrosion resistance becomes the deciding factor, for overall resistance to general uniform corrosion, the common austenitic stainless steel Type 304(L) SS, 18/8(L) SS, is used. This has limitation with respect to uniform corrosion in reducing acids and to pitting corrosion, crevice corrosion and stress corrosion cracking in chloride containing media. In such situations, Type 316(L) SS, 18/8/2.5Mo/(L), shows somewhat better performance. These are called Standard Austenitic Stainless Steels. Even 316(L) SS shows unsatisfactory corrosion behavior in strong reducing acids, in concentrated chloride solutions at elevated temperatures and in fluids flowing with high velocities. In such cases, if the process conditions cannot be made milder with respect to corrosion phenomena, then there is a strong potential for upgrading the MOCs to Special Stainless Steels. These special stainless steels are either high nickel high molybdenum (~25 % Ni and ~6 % Mo) Super Austenitic Stainless Steels or low nickel (4 to 7 %) Duplex Stainless Steels. With respect to cost, the former are highly expensive than 316(L) SS because of widely varying amounts of nickel and of the presence of high molybdenum and the latter are marginally comparable with 316L SS. It is a common experience in industry that the usage of such special stainless steels is felt necessary only after facing severe corrosion problems in equipments made of standard stainless steels. The purpose of this paper is to present a few case studies of severe corrosion problems analyzed by the author resulting in recommendation of special stainless steel as the corrosion preventive step. The following case studies would be presented. Fertilizer Industry, Ammonia plant, Synthesis Gas Coolers Petrochemical Plant, Proprietary Amine manufacturing Reactor in the presence of Orthophosphoric Acid Petrochemical Plant, Proprietary Amine manufacturing process, Ammonia recovery column. Petrochemical Plant, Reboiler Tubes processing concentrated acetic acid.

REMANIT 4401

Alloy Digest ◽  
1996 ◽  
Vol 45 (12) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Elevated Temperatures ◽  
Austenitic Stainless Steels ◽  
High Strength ◽  
Heat Treating ◽  
Good Resistance ◽  
Temperature Performance ◽  
Textile Industries

Abstract Remanit 4401 is a chromium-nickel-molybdenum austenitic stainless steel. The molybdenum (2 to 2.5%) gives it resistance to pitting corrosion, more than most of the standard grades of austenitic stainless steels. This extra measure of corrosion resistance makes this grade particularly suitable for uses involving severe corrosive conditions. The alloy has high strength and good resistance to creep at elevated temperatures. Its many applications include the nuclear, chemical, food, paper, and textile industries. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, and joining. Filing Code: SS-664. Producer or source: Thyssen Stahl AG.

ALZ 316

Alloy Digest ◽  
1999 ◽  
Vol 48 (8) ◽  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Physical Properties ◽  
Tensile Properties ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Heat Treating

Abstract ALZ 316 is an austenitic stainless steel with good formability, corrosion resistance, toughness, and mechanical properties. It is the basic grade of the stainless steels, containing 2 to 3% molybdenum. After the 304 series, the molybdenum-containing stainless steels are the most widely used austenitic stainless steels. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-756. Producer or source: ALZ nv.

ALLOY 0Cr25Ni6Mo3CuN

Alloy Digest ◽  
1998 ◽  
Vol 47 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Temperature Performance ◽  
Steel Research ◽  
Oil Refinement

Abstract ALLOY 0Cr25Ni6Mo3CuN is one of four grades of duplex stainless steel that were developed and have found wide applications in China since 1980. In oil refinement and the petrochemical processing industries, they have substituted for austenitic stainless steels in many types of equipment, valves, and pump parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming and joining. Filing Code: SS-706. Producer or source: Central Iron & Steel Research Institute.

CARTECH 347

Alloy Digest ◽  
2021 ◽  
Vol 70 (9) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Intergranular Corrosion ◽  
Austenitic Stainless Steels ◽  
Heat Treating ◽  
Intermittent Heating ◽  
Technology Corporation ◽  
Carpenter Technology Corporation

Abstract CarTech 347 is a niobium+tantalum stabilized austenitic stainless steel. Like Type 321 austenitic stainless steel, it has superior intergranular corrosion resistance as compared to typical 18-8 austenitic stainless steels. Since niobium and tantalum have stronger affinity for carbon than chromium, carbides of those elements tend to precipitate randomly within the grains instead of forming continuous patterns at the grain boundaries. CarTech 347 should be considered for applications requiring intermittent heating between 425 and 900 °C (800 and 1650 °F). This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-1339. Producer or source: Carpenter Technology Corporation.

scholarly journals Surface Modification of a Nickel-Free Austenitic Stainless Steel by Low-Temperature Nitriding

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1845
Author(s):  
Francesca Borgioli ◽  
Emanuele Galvanetto ◽  
Tiberio Bacci
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Stainless Steels ◽  
Volume Fraction ◽  
Surface Hardness ◽  
Austenitic Stainless Steels ◽  
Surface Layers ◽  
Modified Surface

Low-temperature nitriding allows to improve surface hardening of austenitic stainless steels, maintaining or even increasing their corrosion resistance. The treatment conditions to be used in order to avoid the precipitation of large amounts of nitrides are strictly related to alloy composition. When nickel is substituted by manganese as an austenite forming element, the production of nitride-free modified surface layers becomes a challenge, since manganese is a nitride forming element while nickel is not. In this study, the effects of nitriding conditions on the characteristics of the modified surface layers obtained on an austenitic stainless steel having a high manganese content and a negligible nickel one, a so-called nickel-free austenitic stainless steel, were investigated. Microstructure, phase composition, surface microhardness, and corrosion behavior in 5% NaCl were evaluated. The obtained results suggest that the precipitation of a large volume fraction of nitrides can be avoided using treatment temperatures lower than those usually employed for nickel-containing austenitic stainless steels. Nitriding at 360 and 380 °C for duration up to 5 h allows to produce modified surface layers, consisting mainly of the so-called expanded austenite or gN, which increase surface hardness in comparison with the untreated steel. Using selected conditions, corrosion resistance can also be significantly improved.

Corrosion Resistance of Nickel-Free Austenitic Stainless Steels and their Nanocomposites with Hydroxyapatite in Ringer's Solution

2011 ◽  
Vol 674 ◽  
pp. 159-163 ◽  
Author(s):  
Maciej Tulinski ◽  
Mieczyslaw Jurczyk
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Mechanical Alloying ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Orthopedic Implants ◽  
Corrosion Current ◽  
Similar Process ◽  
Distinct Advantage ◽  
Ion Release

In this work Ni-free austenitic stainless steels with nanostructure and their nanocomposites were synthesized by mechanical alloying (MA), heat treatment and nitriding of elemental microcrystalline Fe, Cr, Mn and Mo powders with addition of hydroxyapatite (HA). Microhardness and corrosion tests' results of obtained materials are presented. Mechanical alloying and nitriding are very effective technologies to improve the corrosion resistance of stainless steel. Decreasing the corrosion current density is a distinct advantage for prevention of ion release and it leads to better cytocompatibility. Similar process in case of nanocomposites of stainless steel with hydroxyapatite helps achieve even better mechanical properties and corrosion resistance. Hence nanocrystalline nickel-free stainless steels and nickel-free stainless steel/hydroxyapatite nanocomposites could be promising bionanomaterials for use as a hard tissue replacement implants, e.g. orthopedic implants.

Effect of Rare Earth on the Inclusions and Pitting Resistance of Austenitic Stainless Steel

2013 ◽  
Vol 718-720 ◽  
pp. 29-32 ◽  
Author(s):  
Xiao Liu ◽  
Yu Bo
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Austenitic Stainless Steel ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Anodic Polarization ◽  
Austenitic Stainless Steels ◽  
Metallographic Examination ◽  
Pitting Corrosion Resistance

The anodic polarization curves of 21Cr-11Ni austenitic stainless steels with various RE contents in 3.5% NaCl neutral solutions have been measured by electrochemical methods. The effect of RE on pitting corrosion resistance of 21Cr-11Ni stainless steels has been studied by the metallographic examination. The results show that sulfide and other irregular inclusions are modified to round or oval-shaped RE2O2S and RES after adding RE to 21Cr-11Ni stainless steesl. RE makes sulfide, and other irregular inclusions change to dispersed round or oval-shaped RE inclusions, effectively inhibits the occurrence of pitting corrosion, thereby enhancing the corrosion resistance of 21Cr-11Ni austenitic stainless steels.

scholarly journals A Study on Unification of Welding Consumables in Construction of Chemical Cargo Tanker Made of Duplex Stainless Steel: Evaluation of Static Strength of Welded Joint

2019 ◽  
Author(s):  
Takayuki Yotsuzuka ◽  
Yusuke Endo ◽  
Eiji Niino ◽  
Koji Gotoh
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Static Strength ◽  
Clad Steels ◽  
Clad Steel ◽  
Welding Consumables ◽  
Welding Materials

Abstract Austenitic stainless steels such as SUS 316 LN and austenitic stainless clad steel are used in cargo holds of chemical tankers owing to their corrosion resistance. Recently, the use of duplex stainless steels has been increasing, owing to their better strength and corrosion resistance and lower content of expensive Ni, compared with those features of austenitic stainless steels. However, few duplex stainless clad steels have been approved by classification bodies. Furthermore, the application of duplex stainless steel is not yet mainstream as hull structural materials because a stable supply market has yet to be established. Therefore, when applying cladding steel to construction of chemical tankers, austenitic stainless clad steel is often used at present. The duplex stainless steel and the austenitic stainless clad steel are mixed at construction factories; hence, there is a risk of misuse of welding consumables. If misuse is suspected, it is not possible to judge the erroneous use from visual inspection after construction; therefore it is necessary to uniformly remove the weld and re-weld. However, if universal welding consumables were identified, this might avoid the problems of misuse and simplify the procurement of welding materials. In this paper, we report on our studies to verify welding consumables for use in the hull structures, involving a mixture of duplex stainless steel and the austenitic stainless clad steel. The static strength of the welded joints is a particular focus of this study, from which we confirmed the validity and limitations of welding consumables.

CARLSON ALLOY 926 Mo

Alloy Digest ◽  
2002 ◽  
Vol 51 (1) ◽  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Nickel Alloys ◽  
Austenitic Stainless Steels ◽  
Cost Effective ◽  
Oil Platforms ◽  
Alloy 926 ◽  
Corrosive Environments

Abstract Carlson alloy 926 Mo is a superaustenitic 6% Mo stainless steel that resists highly corrosive environments and has excellent chloride pitting, crevice, and stress-corrosion cracking resistance. It can be utilized where the performance of conventional austenitic stainless steels is bor-derline, or as a cost-effective substitute for nickel alloys. The higher mechanical properties that allow designs with thinner sections than con-ventional stainless steels are highly desired for oil platforms. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: SS-842. Producer or source: G.O. Carlson Inc., Electralloy.

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