303 Oţel inoxidabil 1.4305(UNS S30300)

What is stainless steel 303 (UNS S30300)1.4305?

Oţel inoxidabil 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 Tip 1) or Selenium (AMS 5640 Tip 2).

303 oţel inoxidabil 1.4305 Forms

• 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.

Applications for 303 oţel inoxidabil

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

UE ÎN	STATELE UNITE ALE AMERICII –	Japonia EL	Franţa Afnor	Anglia BS	Suedia SS
X8CrNiS18-9	303	SUS303	Z8CNF18-09	303S31	2346

Composition  pentru 303 grade of stainless steel

Proprietăți mecanice 

Grad	303
Rezistență la tracțiune (MPa)	500-750 MPa
Proof Stress (MPa)	190 Min MPa
Elongation A5 mm	35 Min %
Hardness Brinell	230 Max HB

Physical Properties

Physical Property	Valoare
Densitate	8.03 g/cm³
Punct de topire	1455 ° C.
Expansiune termică	17.3 x10^-6 /K
Modul de elasticitate	193 GPA
Conductivitate termică	16.3 W/m.k
Rezistivitate electrică	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.

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

ÎN 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

Tratament termic

ANNEALING

This operation should be carried out at 1850/1950 ºF (1010/1065ºC) followed by water quenching. Tip 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.

Lucrare la cald

Fabrication methods like forging, Acest lucru implică funcționarea fierbinte ar trebui să apară după încălzirea uniformă la 1149-1260 ° C. Componentele fabricate ar trebui apoi răcite rapid pentru a asigura rezistența maximă la coroziune.

MACHINABILITY

• Grad 303 stainless steel has excellent machinability. Machining can be enhanced by adhering to the following rules:
• Tăierea marginilor trebuie păstrate ascuțite. Dull edges cause excess work hardening.
• Tăieturile ar trebui să fie ușoare, dar suficient de adânci pentru a preveni întărirea muncii, călărind pe suprafața materialului.
• Breakers de cipuri ar trebui să fie angajați pentru a ajuta la asigurarea SWARF rămâne clar de muncă
• Conductivitatea termică scăzută a aliajelor austenitice are ca rezultat concentrarea căldurii la marginile de tăiere. Acest lucru înseamnă că lichidele de răcire și lubrifianți sunt necesare și trebuie utilizate în cantități mari.

Sudare

Sudarea 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.

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