UNS S20400 / Nitronic 30 SS Special Alloys For Automotive With Excellent Fabricability

Stainless steel UNS S20400 (Nitronic 30) for automotive hose clamps, safety belt anchors, truck and bus frames etc

1 PRODUCT

Stainless steel UNS S20400 (Nitronic 30) for automotive hose clamps, safety belt anchors, truck and bus frames etc.

Product available in forms of bar, rod, wire, forging billets, sheet, strip, foil, extrusions, seamless tubing etc.

2 APPLICATION

Specific potential applications include automotive hose clamps, safety belt anchors, truck and bus frames, water supply and control structures, sewage treatment plant structures, bulk solids handling equipment, magnetic ore separator screens, coal buckets and hopper cars.

Stainless steels have served successfully in many structural components in the transportation industry. Bus space frames and bumpers take advantage of the excellent fabricability and high strength and toughness of stainless. Tensilized NITRONIC 30 Stainless Steel has been used in rapid transit structurals where the strength-to-weight ratio of up to three times that of carbon steel has improved operating efficiency. Rear frames of refrigerated trucks are easily welded and formed from NITRONIC 30 Stainless Steel, resulting in protective units that can withstand impact blows without cracking. Shipboard container structurals use stainless steel successfully because carbon steel becomes scuffed and rusts wherever the paint is damaged.

3 OVERVIEW

NITRONIC 30 is a nitrogen-strengthened austenitic stainless steel developed for applications requiring a good level of aqueous corrosion resistance combined with good toughness and economy. NITRONIC 30 Stainless Steel provides approximately 50% higher yield strength than Type 304L and, therefore, may allow lighter gages to further reduce costs. NITRONIC 30 Stainless Steel work hardens rapidly while retaining good ductility. Unlike other nitrogen-strengthened stainless steels, NITRONIC 30 Stainless Steel is subject to magnetic transformation when cold worked.

NITRONIC 30 Stainless Steel offers significantly higher strength than Type 304 and potential for applications requiring good resistance to aqueous and atmospheric corrosion resistance combined with good toughness and economy.

NITRONIC 30 Stainless Steel is subject to magnetic transformation and Transformation Induced Plasticity (TRIP) behavior when cold worked.

It is characterized by

• Good wet abrasion resistance

• Good resistance to aqueous and atmospheric corrosion

• High strength

• Economy

4 CHEMICAL COMPOSITION (wt%):

5 PHYSICAL PROPERTY

Density at 70°F (21°C): 7.862 g/cm³ (0.284lb/in³)

Specific heat (Btu/lb/Deg F - [32-212 Deg F]): 0.11

Poissons ratio: 0.298

Modulus of elasticity tension: 28.1

Modulus of elasticity at 70°F (21°C): 28.0 x 10⁶ psi (0.193 x 10⁶ MPa)

Magnetic Permeability (Annealed)

6 MECHANICAL PROPERTY

Properties acceptable for material specification (up to and including 1/4”(6.1 mm) plate) as listed in ASTM A666

7 WEAR RESISTANCE

It is demonstrated that NITRONIC 30 has outstanding corrosive wear resistance under many different siding conditions. The stainless steels as a class are much more abrasion resistant than abrasion resistant (AR) steels under even mildly corrosive conditions. NITRONIC 30 is more cost effective than Types 409 and 304 which are typically used in wet abrasive applications.

8 CORROSION RESISTANCE

NITRONIC 30 Stainless Steel exhibits good corrosion resistance to a variety of media. Pitting resistance, as measured by tests in 10% FeCl3 solution, is better than Type 304. In sulfuric acid and hydrochloric acid, NITRONIC 30 is much better than Types 409 and 410 and approaches Type 304 in more dilute solutions. However, caution should be used with reducing acids. Activated NITRONIC 30 Stainless Steel may not repassivate when exposed to HCI or H₂SO₄ and significant corrosion may occur.

9 WORKING INSTRUCTION

Forging

Heat to 2000°F, soak to equalize, then heat to 2150°F and equalize prior to forging.

Annealing

Soak at 1900-2050°F, quench quickly in air or water.

Hardening

Hardening this alloy requires cold working. It will not harden with exposure to thermal treatment.

Machinability

Slow speeds, positive feeds and abundant resulphurized lubricant are essential to success in machining this alloy. Speeds and feeds similar to those employed with 316 or 317 stainless are appropriate here. All common machining practices can be used on this material. Chips will be tough and stringy and it is recommended that curlers or breakers are used.

Forming

Pre-heating is not required with this material and all common welding methods including gas tungsten arc, gas metal arc and submerged arc are acceptable. Filler metal selection should be of similar chemistry for maximum strength and resistance to intergranular attack.

Weldability

Early experience with NITRONIC 30 stainless shows good welding characteristics. It can be fusion welded with the usual arc welding processes employed for austenitic stainless steels. NITRONIC 30 provides superior ductility and toughness, as well as resistance to weld cracking without the need for preheating or postheating, as most martensitic and heavygage ferritic stainless steels require.

A small quantity of ferrite will form in autogenous NITRONIC 30 stainless welds to minimize any hot cracking sensitivity. Arc welding parameters more closely approximate those of the other NITRONIC grades (e.g., slower weld travel, hotter shielding gas for GTAW - Ar + 5% H2 or He), rather than the standard austenitic stainless steels. Standard AWS austenitic stainless fillers or the newly included AWS A5.9 and A5.4 NITRONIC fillers (209, 240, 219) can be selected for any particular application.

10 STANDARD SPECIFICATION

ASTM A240 Heat Resisting Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip for Pressure Vessels

ASTM A666 Austenitic Stainless Steel Sheet, Strip, Plate and Flat Bar.

11 COMPETITIVE ADVANTAGE:

(1) More than 50 years experience of research and develop in high temperature alloy, corrosion resistance alloy, precision alloy, refractory alloy, rare metal and precious metal material and products.
(2) 6 state key laboratories and calibration center.
(3) Patented technologies.
(4) Ultra-purity smelting process VIM + IG-ESR + VAR.

(5) High performance material.

12 BUSINESS TERM