Posted by Avisha Jain - The Steel Pipes Factory
What is Stainless Steel?
Stainless steel is the generic name for a number of different steels used primarily for their resistance to corrosion. Stainless steels are produced by adding at least 11% chromium to steel to produce a thin passive protective layer of Cr2Q3, which promotes corrosion resistance. This is improved by further increasing the chromium content.
Four basic groups of stainless steel are available:
18% chromium, 8% nickel, 0.15% carbon.
Remainder: Fe (S. & P. kept below 0.045%), Ti or Nb.
The nickel is added to give toughness and may be increased to 11.5% to prevent work hardening (for rivets and fastenings). The chromium is added to give corrosion resistance. In addition titanium or niobium is often added to prevent inter-granular corrosion (weld decay) in the following proportions: Ti – 5 x C content, Nb = 10 x C content.
Approximate melting temperature
1420°C to 1395°C
170 Hv (water quench from 1000°C)
Approx. 620 N/mm²
Approx. 280 N/mm²
7.92 g/cm³ at +20°C
Coefficient of linear expansion
This iron-based alloy has a characteristic silver lustre imparted to it by the amount of chromium and nickel. It is the chromium which combines with oxygen and rapidly forms a very thin oxide which is continuous and stable and impervious to further attack by the atmosphere. The thickness of this oxide film increases with the degree of polish to give a mirror finish. These steels give a dull red spark when touched on a grinding wheel.
The corrosion resistance is excellent in most environments but solutions of nitric, hydrofluoric and sulphuric acid will attack 18/8 stainless steel. These acid solutions are used to remove the oxide scale which result from strongly heating the material in air. The term used for this treatment is pickling.
Types of Corrosion:
Stainless steels are used extensively in food and drink production and the chemical and energy industries; martensitics are used for cutlery and other cutting tool manufacture.
Austenitic Stainless Steels
High strength for roll formed structural components
304, 304L, 304H
Standard 18/8 grades
310, 310S, 310H
High temperature resistant grades
316, 316L, 316H
Improved resistance to pitting corrosion in chloride environments
321, 321H, 347
Stabilized grades for heavy section welding and high temperature applications
High resistance to general corrosion, pitting and stress corrosion cracking
Ferritic Stainless Steels
Automotive exhaust grade – weld stabilized
Resistant to mildly corrosive environments
Resistant to mildly corrosive environments – weld stabilized
A ferritic alternative to grade 316 / 316L – weld stabilized
Duplex Stainless Steels
Lean duplex – economical alternative to 304 and 316
Duplex alternative to grade 316
Standard duplex stainless steel - high resistance to pitting and stress corrosion
Super duplex with very high resistance to pitting and stress corrosion
Martensitic Stainless Steels
Standard martensitic grade for low-duty hardened applications
Free-machining bar grade
Higher hardness martensitic grade for cutlery, cutting tools and dies
High hardness and toughness grade, primarily for shafting
440A, 440B, 440C
Very high hardness grades used in cutting tools
Precipitation Hardening Stainless Steel
(17-4PH) High strength shafting grade
Stainless steels have good strength and good resistance to corrosion and oxidation at elevated temperatures. Stainless steels are used at temperatures up to 1700° F for 304 and 316 and up to 2000 F for the high temperature stainless grade 309(S) and up to 2100° F for 310(S).
Effect on Stainless Steel
Forms a passive film with oxygen that prevent the further diffusion of oxygen into the surface
Composition needs to contain at least 10.5% to be a stainless steel
Increases ductility and toughness. Increase corrosion resistance to acids
Additon creates non-magnetic structure
Increases pitting and crevice corrosin resistance. Increase resistance to chlorides
Increase corrosion resistance to sulfuric acid
Substitute for nickel (200 series)
Ties up carbon and prevents inter-granular corrosion in welded zone of ferritic grades
Increase strength and corrosion resistance in austenitic and duplex grades
Improves resistance to high temperature scaling
Usually kept low excet for "free-machining" grades
Usually kept low. Used in martensitic grades to increase strength and hardness
X12CrNi 17 07
14 23 31
14 23 32
X5CrNi 18 10
14 23 33
X2CrNi 18 11
14 23 52
X8CrNi 18 12
X16CrNi 23 14
Z22CrNi 25 20
14 23 61
14 23 40
X8CrNiMo 17 13
14 23 4314 23 47
X2CrNiMo 17 12
14 23 5314 23 48
X2CrNiMo 18 16
14 23 67
14 23 66
14 23 50
X6CrNiTi 18 11
14 23 37
X6CrNiNb 18 11X8CrNiNb 18 11
14 23 38
14 23 01
14 23 20
14 23 25
13 23 02
About The Steel Pipes Factory
Established in 1975, the Metallica Metals Group has its operations spread across major cities in India. We are a pioneer in the stainless steel pipes, carbon steel pipes and alloy steel pipes manufacturing and processing industry. Our products are exported to over 70 countries across the world, while in India we have supplies to even the remote areas. With over 250 tons of sale in stainless steel and carbon steel pipes every day, Metallica has emerged as a prominent vendor for many buyers in India and Overseas.
We procure significant quantities of materials from Indian carbon steel pipe mills and overseas manufacturers of stainless steel pipes. Given our extensive network for sourcing the best quality goods at most competitive prices, we are a preferred seller of steel products for various turnkey projects in India and Worldwide.
Our annual sales volume over 70,000 tonnes in India and Worldwide, has won us the dealership and distributorship of renowned seamless (JINDAL, ISMT) and welded steel pipes manufacturing companies across the globe.
With a team of over 50 people dedicated for deliveries and response to our esteemed customers, we can offer the best service. At the same time, we are also committed to offer best quality products and most competitive prices to our customers. We are professional manufacturer and supplier of stainless steel seamless pipes, with exports all across the globe.
As one of the biggest supplier of A106 seamless steel pipes in India, Metallica carries inventory of over 15,000 tons in its warehouses in Mumbai, Maharashtra India. We sell our ASTM A106 seamless pipe products throughout India, and to international clients. We can supply our ASTM A106 seamless steel pipe products not only in industry-standard lengths and diameters, but also in custom length and diameters. Our range of carbon steel A106 seamless pipes encompasses size range from 1/4 NPS to 24 NPS in thickness upto SCH XXS.
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