303 Stainless steel 1.4305(UNS S30300)

Що таке нержавіюча сталь 303 (UNS S30300)1.4305?

Stainless Steel 303 is the classic free-machining austenitic stainless steel grade. Our material is certified to ASTM F899 (Standard Specification for Wrought Stainless Steel For Surgical Instruments) and ISO 7151 (Surgical Instruments) making it ideal for a range of applications from sanitary wares to micro-mechanical engineering components.

Stainless steel grade 303 can only be strengthened by cold working, not heat treatment, which can lead to the formation of alpha ferrite martensite, considerably increasing its ferromagnetism up to a relative magnetic permeability > 1. The presence of MnS inclusions and of delta ferrite may increasing the difficulty in polishing this grade.

Non-medical versions of 303 stainless steel are available to AMS 5640 in two different types depending on the addition of Sulphur (AMS 5640 Type 1) or Selenium (AMS 5640 Type 2).

303 нержавіюча сталь 1.4305 Формаs

• Round Bars and Rods

303 stainless steel rods and round bars are often used in applications requiring heavy machining to fabricate parts. They are often used in parts such as screws, gears, nuts and bolts, electrical switchgear components, and aircraft fittings.

• Hex Bars and Rods

303 stainless steel hex bars and rods enable faster machining and lower production costs. Although they have less corrosion resistance than other grades of stainless steel, 303 stainless steel hex bars and rods offer excellent toughness.

Square Bars

Square bars made with 303 stainless steel can resist scaling at up to 871 °C. Compared to conventional stainless steel square bars, the sulfur component helps improve turning breakup while simultaneously reducing cutting tool drag.

• Flat Bars

For parts that require sufficient corrosion resistance and need to be machined, ground, or polished, 303 stainless steel flat bars are useful for many applications.

Заявки на 303 нержавіюча сталь

303 stainless steel tube/bar/sheet materials are used in many applications to fabricate a wide range of parts, including:

• Bushings
• Shafts
• Nut and bolts
• Gears
• Electrical switchgear components
• Aircraft fittings

Equivalents of grade 303

ЄС EN	США -	Японія JIS	Франція АЛЕ	Англія БС	Швеція СС
X8CrNiS18-9	303	SUS303	Z8CNF18-09	303S31	2346

Composition  for 303 grade of stainless steel

Механічні властивості 

Клас	303
Tensile Strength (MPa)	500-750 MPa
Proof Stress (MPa)	190 Min MPa
Elongation A5 mm	35 Min %
Hardness Brinell	230 Max HB

Фізичні властивості

Physical Property	Значення
Щільність	8.03 g/cm³
Температура плавлення	1455 °C
Теплове розширення	17.3 x10^-6 /K
Модуль пружності	193 ГПа
Теплопровідність	16.3 W/m.K
Електричний опір	0.72 x10^-6 Ω .m

Corrosion and Oxidisation Resistance of 303

303 Stainless Steel shows good corrosion and oxidisation resistance in mildly corrosive atmospheric environments. Its sulphide inclusions act as pit initiation sites meaning it provides a lot less resistance than 304.

Grade 303 should not be exposed to marine or other similar environments, to prevent rapid pitting corrosion.

EN 1.4305 303 Stainless Steel provides good oxidisation resistance in intermittent service to 760°C (1400°F) and continuous service to 870°C (1,598°F)

The use of 303 stainless steel is not recommended in the range of 425-860°C (797-1580°F) due to carbide precipitation.

303 is susceptible to sensitisation.

HEAT RESISTANCE

• Good oxidation resistance at temperatures up to 1700oF (927 oC)
• Continuous use at temperatures above 1400oF (760oC) is not usually recommended due to carbide precipitation which can lead to irregular scaling
• Does not have a low carbon content so it is also vulnerable to sensitisation

Термічна обробка

ANNEALING

This operation should be carried out at 1850/1950 ºF (1010/1065ºC) followed by water quenching. Type 303, as type 302, should not be subjected to temperatures between 800/1650 ºF (425/900ºC) nor slowly cooled through that temperature range, to prevent intergranular corrosion.

FORGING STAINLESS STEEL 303

The piece to be forged should be heated to 2100/2300ºF (1150/1260ºC) and not forged below 1700ºF (925ºC.) Parts may be air cooled with no danger of cracking and for maximum corrosion resistance small parts may be water quenched directly off the hammer. Large parts should be annealed after forging.

Cold Working

303 is not readily cold workable. Some cold working is possible but sharp bending should not be attempted.

Гаряча обробка

Fabrication methods like forging, that involve hot working should occur after uniform heating to 1149-1260°C. The fabricated components should then be rapidly cooled to ensure maximum corrosion resistance.

MACHINABILITY

• Grade 303 stainless steel has excellent machinability. Machining can be enhanced by adhering to the following rules:
• Ріжучі кромки повинні бути гострими. Тупі кромки призводять до надмірного зміцнення.
• Порізи повинні бути легкими, але достатньо глибокими, щоб запобігти затвердінню матеріалу, що залишається на поверхні.
• Слід використовувати стружколами, щоб забезпечити відсутність стружки на робочому місці
• Низька теплопровідність аустенітних сплавів призводить до того, що тепло концентрується на ріжучих кромках. Це означає, що мастильно-охолоджувальні рідини необхідні і повинні використовуватися у великих кількостях.

Welding

Welding of 303 Stainless is not recommended however if this is if unavoidable then use 308L or 309 for electrodes. 303 must be annealed for optimal corrosion protection.

For optimal annealing heat to 1010-1120°C (1850-2048°F) and cool rapidly with air or water.

EN 1.4305 303 stainless steel cannot be hardened by thermal treatment.°