304 vs 304L vs 304H Stainless Steel: What L and H Mean, Carbon, Welding, Heat & Which to Buy
304, 304L and 304H start from the same 18/8 chromium-nickel austenitic stainless steel. What separates them is the carbon limit, and nothing else. "L" stands for low carbon, capped at 0.030%, meant for welded parts that need to hold onto their corrosion resistance after welding. "H" means controlled high carbon, 0.04–0.10%, chosen for strength in sustained high-temperature service. Plain 304 falls between the two, capped at 0.07% under current ASTM A240, though older editions and IS 6911 allow up to 0.08%.
Chromium, nickel, density, base-metal corrosion resistance: all effectively identical across the three. The carbon figure on the mill test certificate is what tells you which grade you're actually holding.
That sums up the whole 304 vs 304l vs 304h difference (the difference between 304 304l and 304h) in a single line. Three grades, one base chemistry. What changes is the carbon content, and that number decides whether you're buying steel for welding, for heat resistance, or for general-purpose work.
These three grades are Jindal Stainless Limited (JSL) stainless flat products, supplied by Relinox as an MoU partner of Jindal Stainless. They aren't Jindal SAW, JSPL, or JSW pipe or carbon-steel material. And "high carbon" 304H is still a stainless grade. It isn't high-carbon steel.
By the Relinox Technical Team · values per ASTM A240 (UNS S30400 / S30403 / S30409) · last reviewed October 2026.
Quick answer: 304 vs 304L vs 304H at a glance
The difference between ss 304, 304l and 304h (or, as buyers in the Delhi market call it, 304 304l 304h me antar) comes down to carbon. Plain and simple. What that carbon does at the welding torch, and later in the furnace, is what separates the three. Read the 304h vs 304 vs 304l chart below left to right: carbon goes up, weld-zone safety goes down, hot strength goes up. That same 304 vs 304l vs 304h chart works as the decision table for ss 304 vs 304l vs 304h:
| Grade | Carbon (C) | What the letter means | Strength (min, annealed) | Welding | High temperature | Choose when | Relinox supply |
|---|---|---|---|---|---|---|---|
| 304L (S30403) | ≤0.030% | L = low carbon | Tensile 485 MPa · Yield 170 MPa | Best, weld as-is, resists sensitization | Lowest creep strength | Welded tanks, vessels, pharma/dairy, thick welded sections, cryogenic | Core supply |
| 304 (S30400) | ≤0.07% (A240); ≤0.08% older editions / IS 6911 | Standard 18/8 grade | Tensile 515 MPa · Yield 205 MPa | Good on thin sheet with controlled heat input | Moderate | Ambient general fabrication, forming, kitchen, cladding | Core supply |
| 304H (S30409) | 0.04–0.10% | H = high (controlled-minimum) carbon + coarse grain | Tensile 515 MPa · Yield 205 MPa | Weldable, but most sensitization-prone of the three | Best of the three for sustained hot service | Boiler, heat-exchanger, furnace parts | Against indent / on request |
So, which is better 304 or 304l or 304h? None of them dominates across the board. 304L is the right call for welded fabrication. 304H takes the lead on creep strength at elevated temperature. Plain 304 stays the economical all-rounder for ambient service. The sections below break down the 304 vs 304l vs 304h table data element by element.
What do "L" and "H" mean in stainless steel grades?
What does l and h mean in stainless steel grades? The L and H stand for how tightly the carbon content gets controlled. Nothing else about the base chemistry shifts.
- What does L mean in 304L? L stands for low carbon. If you're asking what is L in ss 304l, it's a cap of 0.030% carbon, less than half of plain 304's limit. The low carbon stainless steel 304l meaning in practice comes down to this: there's too little carbon to form chromium carbides at grain boundaries during welding, so the weld zone keeps its corrosion resistance without post-weld annealing.
- What does H mean in 304H? H stands for high carbon, but "high" only relative to 304L. Under ASTM A240, the h grade stainless steel meaning is a carbon band with a floor (0.04–0.10%), plus a coarse-grain requirement. Both exist for one reason: to deliver creep and stress-rupture strength above roughly 500 °C.
- N = nitrogen-strengthened. You may see 304n or 304ln on some drawings. Nitrogen raises strength, and in 304LN it restores the yield lost by lowering carbon. These are specialised variants, available on request or against indent only.
The same suffix logic carries through the entire austenitic family. 316L, 321H - same rules apply. For the molybdenum side of that same L story, see the same L logic in 316 vs 316L.
Carbon: the one real difference (304 vs 304L vs 304H carbon content)
Low carbon vs high carbon 304 traces back to carbon doing two opposing things inside an 18/8 austenitic steel.
- Weld-zone corrosion. Hold stainless steel somewhere in the 425–870 °C range, whether during welding or just in hot service, and carbon starts bonding with chromium at the grain boundaries, forming chromium carbide. That leaves the steel next to those boundaries short on chromium, and it can corrode right along the grains. Less carbon means less risk. That's the reason 304L exists.
- High-temperature strength. At sustained elevated temperatures, carbon held in solution, paired with a coarser grain, resists creep. More carbon, within limits, means more strength. Which is why 304H exists.
The 304 vs 304l vs 304h carbon content falls into three distinct windows. Below is the complete 304 vs 304l vs 304h composition per ASTM A240. These values for 304 vs 304l vs 304h chemical composition line up with what's shown on our SS 304 grade, full composition & properties page, as well as the 304L and 304H grade pages:
| Element (%) | 304 (S30400) | 304L (S30403) | 304H (S30409) |
|---|---|---|---|
| Carbon (C) | ≤0.07 (≤0.08 in older editions / IS 6911) | ≤0.030 | 0.04–0.10 |
| Chromium (Cr) | 18.0–20.0 | 18.0–20.0 | 18.0–20.0 |
| Nickel (Ni) | 8.0–10.5 | 8.0–12.0 | 8.0–10.5 |
| Manganese (Mn), max | 2.00 | 2.00 | 2.00 |
| Silicon (Si), max | 0.75 | 0.75 | 0.75 |
| Phosphorus (P), max | 0.045 | 0.045 | 0.045 |
| Sulphur (S), max | 0.030 | 0.030 | 0.030 |
| Nitrogen (N), max | 0.10 | 0.10 | Not separately limited in A240 |
| Grain size | Not specified | Not specified | ASTM No. 7 or coarser |
The 304h grain size requirement is the second thing, right after carbon, that separates a genuine 304H certificate from a plain 304 certificate that merely shows 0.05% carbon. It calls for ASTM grain size No. 7 or coarser. The astm a240 304 304l 304h limits are summarized on our ASTM A240 limits page.
Strength compared: 304 vs 304L vs 304H mechanical properties
Carbon makes the difference in the 304 vs 304l vs 304h mechanical properties comparison. 304L trades some minimum strength for its lower carbon content. 304 and 304H, though, share identical room-temperature minimums. Below are the annealed sheet and plate minimums per ASTM A240: the 304 vs 304l vs 304h tensile and 304 vs 304l vs 304h yield figures.
| Property (annealed) | 304 | 304L | 304H |
|---|---|---|---|
| Tensile strength, min | 515 MPa | 485 MPa | 515 MPa |
| Yield strength 0.2%, min | 205 MPa | 170 MPa | 205 MPa |
| Elongation in 50 mm, min | 40% | 40% | 40% |
| Hardness, max | 201 HBW / 92 HRB | 201 HBW / 92 HRB | 201 HBW / 92 HRB |
| Density (approx.) | ~8.0 g/cm³ | ~7.9–8.0 g/cm³ | ~8.0 g/cm³ |
| Magnetic (annealed), 304 vs 304l vs 304h magnetic | Non-magnetic | Non-magnetic | Non-magnetic |
304L carries a lower minimum yield than 304, 170 MPa against 205 MPa, and that gap only matters when a design is strength-limited. The fix is simple enough: go slightly thicker in section, or specify dual-certified 304/304L sheet that still meets 304's minimums. Heat flips this picture. At elevated temperature the advantage swings firmly to 304H, and that's exactly where its allowable stresses come from.
On 304 vs 304l vs 304h density and 304 vs 304l vs 304h weight: all three come in around 8.0 g/cm³, so an 8x4 sheet of a given thickness weighs the same no matter which grade you pick. Check the stainless steel weight calculator or the SS sheet weight chart for exact figures.
Welding & sensitization: 304, 304L or 304H?
304L or 304H for welding? Go with 304L almost every time. 304H earns its place for heat resistance, not weldability. For the full two-way breakdown, see our 304L vs 304 in detail page. The three-way summary follows below.
Why 304L for welded fabrication
304 sensitization is the risk that a weld's heat-affected zone, after passing through the carbide-forming range, corrodes preferentially down the line. On thick sections, multi-pass welds and joints that cool slowly, plain 304 can sensitize. 304L, with ≤0.030% carbon, doesn't form enough carbide for it to matter. Intergranular corrosion 304 vs 304l favors 304L wherever the welded part ends up in wet, acidic or cleaning-chemical service: tanks, vessels, pipework spools cut from sheet, sanitary equipment. So, which is better for welding 304 or 304l? For heavy or critical welded work, 304L wins. In the market's own words, welding ke liye 304 ya 304l? 304L.
When plain 304 is fine to weld
On thin sheet, roughly up to 3 mm, welded with quick, controlled heat input for kitchen counters, cabinets, railings, ducting, the time spent in the sensitization range is short. Plain 304 welds without trouble here. Most ambient fabrication in India is done this way on 304.
Welding 304H
Can 304h be welded? Yes, and 304h welding happens all the time in boiler and pressure-part shops. Shops typically use a matching high-carbon filler, such as 308H, so the weld retains comparable creep strength. There's a catch, though: 304H is the most sensitization-prone of the three 304 grades, which is why it suits parts that run hot in dry service rather than welded parts that will later face wet corrosion. Filler choice and welding procedure ultimately rest with your qualified WPS.
High-temperature service: why 304H exists
304h high temperature service is the entire reason the grade exists. With its controlled carbon band and coarse grain, 304H holds allowable stress in sustained hot service from around 500 °C upward. 304L softens there, and plain 304 falls behind.
On the 304h max temperature question: the published guideline on our grade page runs to about 800 °C continuous. It's application-dependent, and design allowables are governed by your pressure code. For the depth on 304h vs 304l high temperature behaviour, see the 304H high-temperature grade page.
Alternatives, 304 vs 321 vs 304H for high temperature: where welded parts also need to resist intergranular attack after hot exposure, titanium-stabilised SS 321 is the usual pick. For oxidation resistance at still higher temperatures, the 25Cr/20Ni SS 310S heat-resistant grade takes over. Plain 304 stays the economical choice, but only for intermittent or moderate heat.
Corrosion resistance: 304 vs 304L corrosion resistance
In the base metal, before any welding happens, 304 vs 304l corrosion resistance comes out equal, and 304H matches both: same 18–20% chromium, same 8%+ nickel. The differences show up only in heat-affected zones. 304L holds onto its resistance after welding. 304 can lose it on thick welds. 304H ends up the most exposed after hot service. None of the three has molybdenum in it, so for chlorides, coastal air or brine, step up to the 316 family. The 304l vs 316l choice really comes down to a chloride question; see SS 316L and 304 vs 316.
Dual-certified 304/304L sheet
A 304 304l dual certified sheet is one lot whose chemistry hits 304L's carbon cap (≤0.030%) while its mechanicals clear 304's higher minimums: tensile 515 MPa, yield 205 MPa. Mills do this routinely under ASTM A240, which is exactly why fabricators so often see no price gap between the two grades. The 304/304l dual grade meaning boils down to this: one sheet, honestly usable as either grade, both designations stamped on a single certificate.
On a dual certified stainless steel MTC, the grade line reads 304/304L (or both UNS numbers, S30400/S30403). Carbon sits at or below 0.030%, with tensile and yield results above 304 minimums. Need dual certification for your drawing? Note it on your indent, and we'll confirm whether a given lot is offered dual-certified.
Which one should you buy? Use-case verdicts
Here are the 304 vs 304l vs 304h uses, and the 304 vs 304l vs 304h applications, by job:
| Application | Recommended grade | Why | Related page |
|---|---|---|---|
| Commercial kitchen equipment, counters, sinks | 304 | Thin sheet, ambient service, good forming | Kitchen equipment |
| Wall cladding, interiors, railings | 304 | Ambient, cosmetic, mostly light welding | Cladding & interiors |
| Welded storage tanks and process vessels | 304L | Thick welds without sensitization | Water storage tanks |
| Pharma and dairy equipment | 304L (316L where chlorides/CIP chemicals are aggressive) | Weld-zone corrosion resistance, hygiene | Pharma & dairy equipment |
| Chemical process plant (mild media) | 304L | Welded, wet service | Chemical process plants |
| Cryogenic / low-temperature service | 304L | Austenitic toughness at sub-zero, welded | SS 304L |
| Boiler, superheater, heat-exchanger parts | 304H | Creep strength in sustained hot service | SS 304H |
| Furnace parts, hot ducting | 304H, or 321 / 310S | 304H for creep; 321 if welded + wet; 310S for oxidation | SS 310S |
On 304 vs 304l for pharma or dairy, the welds are the weak point, which settles it: go with 304L. 304h for boiler, heat exchanger or furnace parts? Yes, where creep governs. 304l for cryogenic or low temperature service? Yes too, since welded austenitic stainless keeps its toughness well below zero.
Cost & availability in India
On 304 vs 304l vs 304h price: the price difference between 304 and 304L is usually modest, and dual-certified 304/304L lots often erase it entirely. 304H is a different story. It's a specialised product supplied against indent, which usually means a premium and a longer mill lead time. Prices for all three track nickel, thickness, finish and order quantity, so quotes shift from one day to the next.
We skip exact figures in our guides. Looking for a 304l sheet price per kg, a 304h sheet rate today, or the market's 304l ka rate and 304h ka bhav? Check today's indicative 304 price list, then confirm today's rate on the RFQ form. Commercial basis: prices ex-Delhi, GST and freight extra. No minimum order quantity. Cut-to-size pieces are available on request at an additional charge.
How to verify 304L or 304H on the mill test certificate
The Jindal MTC settles it: the carbon value is the proof. For 304l mtc carbon checks, and more broadly for how to check 304l on mill certificate, match these fields against the heat number stamped on the sheet:
| Field on MTC | What 304L must show | What 304H must show |
|---|---|---|
| Grade / UNS | 304L, UNS S30403 (or dual 304/304L) | 304H, UNS S30409 |
| Carbon (C) | ≤0.030% | Between 0.04% and 0.10% |
| Cr / Ni | Cr 18.0–20.0, Ni 8.0–12.0 | Cr 18.0–20.0, Ni 8.0–10.5 |
| Tensile / yield | ≥485 / ≥170 MPa (≥515 / ≥205 if dual-certified) | ≥515 / ≥205 MPa |
| Grain size | Not required | ASTM No. 7 or coarser |
| Heat number | Must match the sheet marking | Must match the sheet marking |
| Standard | ASTM A240 / IS 6911 | ASTM A240 |
A 304 sheet with 0.05% carbon is still a 304 sheet. Without the grade designation and the grain-size result, it isn't 304H. More on reading certificates at quality & mill test certificates.
Designations: UNS S30400 vs S30403 vs S30409
Plain 304 is the trade's "18/8," known in the Delhi market as 304 ka steel or 304 maal. 304L often shows up written as 304 low carbon, while 304H appears on drawings as 304 high carbon or high-temperature 304. For tenders and import equivalents, whether it's UNS S30400 vs S30403 vs S30409 or the European terms EN 1.4301 vs 1.4307 vs 1.4948, the 304/304L/304H difference in designations comes down to this:
| Grade | AISI | UNS | EN | JIS |
|---|---|---|---|---|
| 304 | 304 | S30400 | 1.4301 | SUS 304 |
| 304L | 304L | S30403 | 1.4307 (older 1.4306) | SUS 304L |
| 304H | 304H | S30409 | 1.4948 | SUS 304H |
Indian sheet comes to ASTM A240 and IS 6911. 304H, though, is quoted to ASTM A240 / UNS S30409.
Buying 304 / 304L / 304H from Relinox
On jindal 304 vs 304l: both are core Jindal Stainless grades we supply, with MTC. Looking for jindal 304l sheet? Check the Jindal 304L sheet page. If you need a jindal ss 304l sheet dealer, a jindal ss 304l sheet stockist, or a jindal ss 304l sheet supplier, the 304L grade page lists sizes and the RFQ form. As for jindal 304h sheet availability: 304H ships against indent or on request, never ex-stock. See 304H sheet against indent if you're after a 304h sheet supplier india or a 304h plate dealer.
Relinox operates as a 304 304l 304h sheet dealer, 304 304l 304h sheet supplier, 304 304l 304h sheet trader and 304 304l 304h sheet stockist from 699, 1st Floor, Gali Kundewalan, Ajmeri Gate, Delhi 110006. Anyone searching for a 304l sheet stockist delhi or a 304l trader ajmeri gate can check our Delhi stainless steel sheet dealer page too.
- Jindal Stainless MoU partner: an authorized channel, selling genuine JSL-melted material (about the partnership).
- MTC with the carbon value, the document that proves L vs H.
- Standard sizes run to 304l sheet 8x4 (1250×2500 mm), 4×10 (1250×3050 mm), and 304h plate 5x10 (1500×3000 mm) against indent. Thickness runs roughly 0.3–12 mm+, in sheet, plate, coil and patta.
- Cut-to-size on request, pan-India dispatch from Delhi, no MOQ; GSTIN 07AAYFR6664H1ZD.
Fabricators: check today's 304/304L rate on the RFQ form. OEMs: need an MTC? Request your quote with it included. 304H buyers: the same form works for you too, just raise a 304H indent enquiry there.
FAQ
What is the difference between 304, 304L and 304H?
Carbon content is where these grades split. Under ASTM A240, 304 tops out at 0.07% carbon. 304L cuts that down to a ceiling of 0.030%, while 304H sits in a narrower band between 0.04% and 0.10%. Chromium and nickel levels don't really change from one to the next. For welding, go with the L grade; when the application calls for strength at high temperatures, H is the better choice.
What does L mean in 304L and H in 304H?
L stands for low carbon, and it keeps the weld zones from sensitizing. H, on the other hand, means a controlled high-carbon band with a coarse grain size; that's what gives you creep strength at high temperature.
Is 304L better than 304?
For welded and thick-section work, yes, since it resists sensitization. Corrosion resistance of the base metal matches standard 304, though 304L's minimum yield sits lower, at 170 MPa against 205 for 304.
304L or 304H for welding?
304L. 304H gets picked for high-temperature strength, not for how it welds, and of the three it sensitizes the most readily.
Is 304L same as 304?
Not quite. Same chromium and nickel, but 304L has lower carbon and a slightly lower minimum strength. Plenty of mill lots come dual-certified 304/304L and satisfy both grades.
Can 304L replace 304?
Usually, yes. Dual-certified 304/304L meets both specifications. Check the design strength if your drawing relies on 304's 205 MPa minimum yield. The reverse case, substituting 304 for 304L, isn't advisable for heavy welded parts.
Can 304 replace 304H?
304 isn't built for code-designed high-temperature parts. It carries no carbon floor and no grain-size requirement, so it simply can't be certified as 304H.
Is 304H high carbon steel?
No. 304H is a stainless steel with only 0.04–0.10% carbon. "High" here means high relative to 304L, nothing close to a high-carbon steel.
Are 304, 304L and 304H magnetic?
All three stay essentially non-magnetic when annealed, though cold working can coax out a slight response. See magnetic vs non-magnetic stainless.
Is 304L more expensive than 304?
Usually they're close, and dual-certified lots often close the gap entirely. 304H is indent material, though, and it typically runs higher priced. Check the indicative 304 price list, and confirm today's rate on the RFQ form.
How do I know my sheet is really 304L?
Confirm the Jindal MTC lists carbon at 0.030% or lower, with UNS S30403 (or 304/304L) noted, and check that the heat number lines up with the marking on the sheet. You can request an MTC along with your quote.
Do you supply 304H, and how fast?
304H ships against indent or on request, never ex-stock. Lead time tracks the mill schedule and gets confirmed on your RFQ.
304 aur 304L me kya fark hai?
304L ka carbon content kaafi kam rakha gaya hai, ≤0.030% tak. Isi wajah se welding ke baad bhi corrosion ka khatra nahi badhta. Chromium-nickel wali baaki chemistry 304 jaisi hi rehti hai, usme koi badlav nahi.
304L kya hota hai, aur 304H kya hai?
304L ka matlab hai low-carbon 304, jo welding ke kaam mein istemal hota hai. 304H alag hai: controlled high-carbon 304, jiska upyog boiler aur garam service mein hota hai. Yeh indent par milta hai.
Is there an MOQ, and are GST/freight included?
There's no minimum order quantity. Prices are ex-Delhi, and GST and freight are extra. Cut-to-size pieces can be arranged on request, at an additional charge.
Related links
- SS 304 grade, full composition & properties
- 304L vs 304 in detail, SS 304L · 304l stainless steel
- 304H high-temperature grade, 304h stainless steel
- Same L logic in 316 vs 316L
- ASTM A240 limits · IS 6911
- SS 321 · SS 310S · SS 316L
- Quality & mill test certificates
- Today's indicative 304 price list
- Pharma & dairy equipment · Chemical process plants
- Stainless steel weight calculator
- Jindal MoU partnership · Request a quote