304L(Cr-Ni)

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1. Introduce

– Composed of approximately 18% Cr and 8% Ni, hence the name 18-8 stainless steel

– Due to its low carbon content, it retains its strength even after heat treatment

– Ultra-low carbon version of 304 stainless steel, containing up to 0.030% carbon

– Better elasticity and weldability than 304 stainless steel due to low carbon content

– UNS S30403

* 18-8 Stainless Steel

– “18-8” : Part of the chemical composition (18 : Cr content, 8 : Ni content)

– Definition : 300 series grade stainless steel containing about 18% chromium and 8% nickel

– Types : 301, 302, 304 stainless steel

* Types of 304 stainless steel : related to carbon content

– 304L : A low carbon version of 304 stainless steel, containing up to 0.3% carbon
→ Due to its low carbon content, it is less likely to cause carbide precipitation when used at temperatures above 425°C and is used to improve weldability

– 304H : High carbon version of 304 stainless steel, containing approximately 0.04-0.1% carbon
→ Good corrosion resistance and resistance to temperature extremes

* Stainless Steel Comparison

Type	Composition	Properties
304	18%Cr, 8%Ni	– Excellent corrosion resistance and machinability, suitable for use in everyday environments (kitchen utensils, building materials, automotive parts, etc.), – Excellent high temperature properties, but corrosion occurs when used for a long time in the temperature range of 425~860℃
316	17%Cr, 10%Ni, and 2Mo (Similar composition to 304, but contains an additional 2-3% Mo)	Better corrosion resistance than 304, suitable for use in marine and chlorinated environments, Excellent performance at temperatures above 843°C and below 454°C
200 Series	Reduced Ni content, increased Mn and N content	Reduced Ni content and increased Mn and N content for lower manufacturing costs, but reduced corrosion resistance compared to 304 and 316

* UNS

Abbreviation for the Unified Numbering System for Metals and Alloys
Unified unique numbering system for metals and alloys
A representative number compatible with metals and alloys defined in several material-related codes, including ASTM, AISI, ASME, AWS, etc.

* S : Heat and corrosion resistant (stainless) steel

2. Property

– Corrosion resistance, intergranular corrosion resistance, weldability, excellent formability

Element	Impact
Cr, Ni	Provides corrosion resistance

[304L Chemical Composition (%)]

C	Mn	P	S
Max. 0.030	Max. 2.00	Max. 0.045	Max. 0.030

Si	Cr	Ni	N
Max. 0.75	18.0~20.0	8.0~12.0	Max. 0.10

[304L Mechanical Properties]

Tensile Strength (Mpa)	Yield Strength (Mpa)	Elongation (%)
Min. 485	Min. 170	Min. 40

[304L Physical Properties]

Density (g/㎤)	Melting Range (℃)	Specific Heat (0-100℃), J/kg*℃
8.0	1400~1450	500

3. Standard & Specification

– Specification : UNS S30403

ASTM	A182, A213, A240, A249, A269, A270, A312, A314
DIN	1.4306, 1.4307
MIL	S-23195, S-4043, S-23196, A-23196

Product Form	AMS	ASTM
Bar, Rod, Forgings	5639, 5647	–
Sheet, Strip	5501, 5511, 5513	–
Tube	5560, 5565, 5566, 5567, 5569, 5575	–
Powder	–	A276

4. Available Form

– Bar, Rod

– Plate, Sheet, Strip

– Coil, Wire

– Tube, Pipe

– Forgings

– Powder

5. Application & Product

– Medical, Construction, Chemical, Automotive, Food

Application	Product
Medical	Surgical instruments, implants
Construction	Exterior wall cladding, handrails, door handles
Chemical	Storage tanks, pipelines
Automotive	Exhaust systems
Food	Kitchen utensils, cookware, food processing equipment