Study on the Machinability of Free Cutting Non-Lead Austenitic Stainless Steels

2012 ◽  
Vol 430-432 ◽  
pp. 306-309 ◽  
Author(s):  
Di Wu ◽  
Zhuang Li

In this paper, a new non-lead machinable austenitic stainless steel was investigated. The metallurgical properties, machinability and mechanical properties of the developed alloy were compared with those of the conventional austenitic stainless steel 321. The results have shown that the presence of machinable additives, such as sulfur, copper and bismuth, etc. contributes to the improvement of the machinability of austenitic stainless steel, because the inclusions are something like internal notches causing crack nucleation and facilitating rupture. Bismuth has a distinct advantage over lead. The machinability of the austenitic stainless steels with free-cutting additives is much better than that of austenitic stainless steel 321. The mechanical properties of the free cutting austenitic stainless steel are similar to those of 321 although the former are slightly lower than those of the latter.

Alloy Digest ◽  
1999 ◽  
Vol 48 (8) ◽  

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.


2013 ◽  
Vol 711 ◽  
pp. 95-98
Author(s):  
Xiao Liu ◽  
Jing Long Liang

The effect of Ce on structure and mechanical properties of 21Cr11Ni austenitic stainless steels were studied by metallographic examination, scanning electron microscope (SEM), tensile test. The results show that the proper amount of Ce can refine microstructure of austenitic stainless steel. Fracture is changed from cleavage to ductile fracture by adding Ce to austenitic stainless steel. 21Cr11Ni stainless steel containing 0.05% Ce can improve its high temerature strength, and the strength is increased 21.81% at 1073K respectively comparing with that of 21Cr11Ni stainless steel without Ce.


Alloy Digest ◽  
2021 ◽  
Vol 70 (9) ◽  

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.


Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1845
Author(s):  
Francesca Borgioli ◽  
Emanuele Galvanetto ◽  
Tiberio Bacci

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.


2011 ◽  
Vol 674 ◽  
pp. 159-163 ◽  
Author(s):  
Maciej Tulinski ◽  
Mieczyslaw Jurczyk

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.


Author(s):  
G. Ubertalli ◽  
M. Ferraris ◽  
P. Matteis ◽  
D. Di Saverio

Lean duplex stainless steels have similar corrosion and better mechanical properties than the austenitic grades, which ensure their extensive spreading in industrial applications as a substitute of austenitic grades. In the construction of liquid tanks, however, it is often necessary to weld such steels with a range of fittings which are commonly fabricated with austenitic stainless steel grades. Therefore, this paper examines dissimilar welded joints between LDX 2101 (or X2CrMnNiN22-5-2) lean duplex stainless steels plates and austenitic stainless steel pipes, carried out by different arc welding processes. The investigation focuses on the correlation between the welding procedures and the microstructural and mechanical properties of the welded joints.


2019 ◽  
Vol 116 (6) ◽  
pp. 618
Author(s):  
Nega Setargew ◽  
Daniel J. Parker

Zinc diffusion-induced degradation of AISI 316LN austenitic stainless steel pot equipment used in 55%Al-Zn and Zn-Al-Mg coating metal baths is described. SEM/EDS analyses results showed that the diffused zinc reacts with nickel from the austenite matrix and results in the formation of Ni-Zn intermetallic compounds. The Ni-Zn intermetallic phase and the nickel depleted zones form a periodic and alternating layered structure and a mechanism for its formation is proposed. The role of cavities and interconnected porosity in zinc vapour diffusion-induced degradation and formation of Ni-Zn intermediate phases is also discussed. The formation of Ni-Zn intermediate phases and the depletion of nickel in the austenite matrix results in the precipitation of σ-phase and α-ferrite in the nickel depleted regions of the matrix. This reaction will lead to increased susceptibility to intergranular cracking and accelerated corrosion of immersed pot equipment in the coating bath. Zinc diffusion induced precipitation of σ-phase in austenitic stainless steels that we are reporting in this work is a new insight with important implications for the performance of austenitic stainless steels in zinc containing metal coating baths and other process industries. This new insight will further lead to improved understanding of the role of substitutional diffusion and the redistribution of alloying elements in the precipitation of σ-phase in austenitic stainless steels.


2019 ◽  
Vol 944 ◽  
pp. 193-198
Author(s):  
Tian Yi Wang ◽  
Ren Bo Song ◽  
Heng Jun Cai ◽  
Jian Wen ◽  
Yang Su

The present study investigated the effect of cold rolling reduction on microstructure and mechanical properties of a 204C2 Cr–Mn austenitic stainless steel which contained 16%Cr, 2%Ni, 9%Mn and 0.083 %C). The 204C2 austenitic stainless steels were cold rolled at multifarious thickness reductions of 10%, 20%, 30%,40% and 50%, which were compared with the solution-treated one. Microstructure of them was investigated by means of optical microscopy, X-ray diffraction technique and scanning electron microscopy. For mechanical properties investigations, hardness and tensile tests were carried out. Results shows that the cold rolling reduction induced the martensitic transformation (γ→α ́) in the structure of the austenitic stainless steel. With the increase of the rolling reduction, the amount of strain-induced martensite increased gradually. Hardness, ultimate tensile strength and yield strength increased with the incremental rolling reduction in 204C2 stainless steels, while the elongation decreased. At the thickness reduction of 50%, the specimen obtained best strength and hardness. Hardness of 204C2 stain steel reached 679HV. Ultimate tensile strength reached 1721 MPa. Yield strength reached 1496 MPa.


2012 ◽  
Vol 512-515 ◽  
pp. 1923-1926
Author(s):  
Zhuang Li ◽  
Di Wu ◽  
Wei Lv

Environmental protection is a growing concern for many industries today. This paper shows manufacturing environmental performance improvement for free cutting steel products. Inclusions have the characteristics of sulfur and bismuth in free cutting austenitic stainless steels without lead addition. Machinable additives lead to improved chip breakage, and thus reduced tool wear. The machinability of free cutting austenitic stainless steels without lead addition is much better than that of conventional austenitic stainless steel. Bismuth can replace lead because lead is a harmful factor for environment and machine operators' health. The reduction of environmentally harmful substances such as lead was performed. A feasible combination of free-cutting additives should yield a stainless steel product with acceptable machining and mechanical properties.


2017 ◽  
Vol 750 ◽  
pp. 26-33
Author(s):  
Alaa Abu Harb ◽  
Ion Ciuca ◽  
Robert Ciocoiu ◽  
Mihai Vasile ◽  
Adrian Bibis ◽  
...  

The welding technique used for ASIS 304 and 316L austenitic stainless steel sheets both with a thickness of 3mm is gas tungsten arc welding (TIG) and manual metal arc welding (MMAW). Mechanical properties that were verified include: hardness test and tensile test before welding and after it. The welding process was done on two types of specimens: with a central hole and without hole. We concluded that there was a decrease in the properties of tensile for both specimens with central hole, and 316L had tensile characteristics better than 304 when using the technique TIG. As for 304, it had tensile characteristics better than 316L when using the technique MMAW. We also concluded that the existence of central holes had an influence on the hardness characteristics on both types. The hardness increased in 304 but decreased in 316L. The welding process also showed that there was no influence of MMAW on hardness on both specimens. However it showed that there was no influence of TIG on the hardness for 304, but for 316L values increased.


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