Difference Between Inconel and Stainless Steel

Inconel Vs Stainless Steel

Inconel

Inconel, a product of Special Metals Corp., has a nickel, chromium and molybdenum composition. Inconel is resistant to corrosion and pitting and comes in several different alloys. Stainless steel is composed of carbon, manganese, phosphorus, sulfur, silicone, chromium and nickel. Both Inconel and stainless steel use a numbering system for different alloys and strengths. These products have silver finishes, but different textures create matte or shiny surfaces.

Cost or Price Difference between Inconel & stainless steel

Inconel is more expensive than stainless steel. For example, exhaust valves for fast cars cost $150 more than stainless, at the time of publication. Special Metals Corp., the inventor of Inconel, sells this alloy in flat sheets, pipes, tubes, flat bars, wire and other shapes. Special Metals shows production of 25 qualities of Inconel. Each product has different characteristics and a different price.

Inconel Composition

Inconel	Element (% by mass)
Inconel	Ni	Cr	Fe	Mo	Nb	Co	Mn	Cu	Al	Ti	Si	C	S	P	B
600	72.0	14.0–17.0	6.0–10.0				1.0	0.5			0.5	0.15	0.015
617	44.2–56.0	20.0–24.0	3.0	8.0–10.0		10.0–15.0	0.5	0.5	0.8–1.5	0.6	0.5	0.15	0.015	0.015	0.006
625	58.0	20.0–23.0	5.0	8.0–10.0	3.15–4.15	1.0	0.5		0.4	0.4	0.5	0.1	0.015	0.015
690	59.5	30	9.2				0.35	0.01	0.02		0.35	0.019	0.003
718	50.0–55.0	17.0–21.0	balance	2.8–3.3	4.75–5.5	1.0	0.35	0.2–0.8	0.65–1.15	0.3	0.35	0.08	0.015	0.015	0.006
X-750	70.0	14.0–17.0	5.0–9.0		0.7–1.2	1.0	1.0	0.5	0.4–1.0	2.25–2.75	0.5	0.08	0.01

Inconel alloys

Alloys of inconel include:

Inconel 600: Solid solution strengthened
Inconel 601
Inconel 625: Acid resistant, good weldability. The LCF version is typically used in bellows.
Inconel 690: Low cobalt content for nuclear applications, and low resistivity
Inconel 713C: Precipitation hardenable nickel-chromium base cast alloy
Inconel 718: Gamma double prime strengthened with good weldability
Inconel 751: Increased aluminium content for improved rupture strength in the 1600 °F range
Inconel 792: Increased aluminium content for improved high temperature corrosion properties, used especially in gas turbines
Inconel 939: Gamma prime strengthened to increase weldability

Inconel Equivalent Grades

STANDARD	WERKSTOFF NR.	UNS	GOST	AFNOR	JIS	BS	EN	OR
Inconel 600	2.4816	N06600	МНЖМц 28-2,5-1,5	NC15FE11M	NCF 600	NA 13	NiCr15Fe	ЭИ868
Inconel 601	2.4851	N06601	XH60BT	NC23FeA	NCF 601	NA 49	NiCr23Fe	ЭИ868
Inconel 617	2.4663	N06617
Inconel 625	2.4856	N06625	ХН75МБТЮ	NC22DNB4M	NCF 625	NA 21	NiCr22Mo9Nb	ЭИ602
Inconel 690	2.4642	N06690
Inconel 718	2.4668	N07718
Inconel 725	-	N07725
Inconel X-750	2.4669	N07750

Inconel Melting Point, Density and Tensile Strength

	Density	Melting Point	Tensile Strength	Yield Strength (0.2%Offset)	Elongation
600	8.47 g/cm3	1413 °C (2580 °F)	Psi – 95,000 , MPa – 655	Psi – 45,000 , MPa – 310	40 %
601	8.1 g/cm3	1411 °C (2571 °F)	Psi – 80,000 , MPa – 550	Psi – 30,000 , MPa – 205	30 %
617	8.3g/cm³	1363°C	≥ 485 MPa	≥ 275 MPa	25 %
625	8.4 g/cm3	1350 °C (2460 °F)	Psi – 135,000 , MPa – 930	Psi – 75,000 , MPa – 517	42.5 %
690	8.3g/cm³	1363°C	≥ 485 MPa	≥ 275 MPa	25 %
718	8.2 g/cm3	1350 °C (2460 °F)	Psi – 135,000 , MPa – 930	Psi – 70,000 , MPa – 482	45 %
725	8.31 g/cm3	1271°C-1343 °C	1137 MPa	827 MPa	20 %
X-750	8.28 g/cm3	1430°C	1267 MPa	868 MPa	25 %

Stainless Steel

Stainless Steel Equivalent Grades

STANDARD	WERKSTOFF NR.	UNS	JIS	BS	GOST	AFNOR	EN
SS 304	1.4301	S30400	SUS 304	304S31	08Х18Н10	Z7CN18‐09	X5CrNi18-10
SS 304L	1.4306/1.4307	S30403	SUS 304L	304S11	03Х18Н11	Z3CN18‐10	X2CrNi18-9 / X2CrNi19-11
SS 310	1.4845	S31000	-	-	-	-	-
SS 310S	1.4845	S31008	SUS310S	-	20Ch23N18	-	X8CrNi25-21
SS 316	1.4401 / 1.4436	S31600	SUS 316	316S31 / 316S33	-	Z7CND17‐11‐02	X5CrNiMo17-12-2 / X3CrNiMo17-13-3
SS 316L	1.4404 / 1.4435	S31603	SUS 316L	316S11 / 316S13	03Ch17N14M3 / 03Ch17N14M2	Z3CND17‐11‐02 / Z3CND18‐14‐032	X2CrNiMo17-12-2 / X2CrNiMo18-14-3
SS 317	1.4449	S31700	SUS 317	-	-	-	X6CrNiMo19-13-4
SS 317L	1.4438	S31703	SUS 317L	-	-	-	X2CrNiMo18154
SS 321	1.4541	S32100	SUS 321	-	08Ch18N10T	-	X6CrNiTi18-10
SS 321H	1.4541	S32109	SUS 321H	-	-	-	X6CrNiTi18-10
SS 347	1.4550	S34700	SUS 347	-	08Ch18N12B	-	X6CrNiNb18-10
SS 347H	1.4961	S34709	SUS 347H	-	-	-	X7CrNiNb18-10
SS 446	1.4762	S44600	-	-	-	-	-

Stainless Steel Composition

Grade	C	Mn	Si	P	S	Cr	Mo	Ni	N
SS 304	0.08 max	2 max	0.75 max	0.040 max	0.030 max	18 – 20	-	8 – 11	-
SS 304L	0.03 max	2 max	0.75 max	0.045 max	0.030 max	18 – 20	-	8 – 12	0.10 max
SS 310	0.25 max	2 max	1.50 max	0.045 max	0.030 max	24 - 26	-	19 - 22	-
SS 310S	0.08 max	2 max	1.50 max	0.045 max	0.030 max	24 - 26	-	19 - 22	-
SS 316	0.08 max	2 max	0.75 max	0.045 max	0.030 max	16 - 18	2 - 3	10 - 14	0.1 max
SS 316L	0.3 max	2 max	0.75 max	0.045 max	0.030 max	16 - 18	2 - 3	10 - 14	0.10 max
SS 317	008 max	2 max	1 max	0.040 max	0.03 max	18 - 20	3 - 4	11 - 14	0.10 max
SS 317L	0.035 max	2 max	1 max	0.040 max	0.03 max	18 - 20	3 - 4	11 - 15	-
SS 321	0.08 max	2 max	0.75 max	0.045 max	0.03 max	17 - 19	5xC min 0.60% max	9 - 12	0.10 max
SS 321H	0.04 - 0.10 max	2 max	0.75 max	0.045 max	0.03 max	17 - 19	4xC min 0.60% max	9 - 12	0.10 max
SS 347	0.08 max	2 max	0.75 max	0.045 max	0.03 max	17 - 20	10xC min 1.00 max	9 - 13	62.74
SS 347H	0.04 – 0.10	2 max	0.75 max	0.045 max	0.03 max	17 - 20	8xC min 1.00 max	9 - 13	62.74
SS 446	0.2 max	1.5 max	0.75 max	0.040 max	0.03 max	23 – 30	0.10 – 0.25	0.50 max	Balance

Stainless Steel Melting Point, Density and Tensile Strength

Grade	Density	Melting Point	Tensile Strength	Yield Strength (0.2%Offset)	Elongation
SS 304	8.0 g/cm3	1400 °C (2550 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 304L	8.0 g/cm3	1400 °C (2550 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	40 %
SS 310	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 310S	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 316	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 316L	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	40 %
SS 317	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 317L	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 321	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 321H	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	35 %
SS 347	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	40 %
SS 347H	8.0 g/cm3	1454 °C (2650 °F)	Psi – 75000 , MPa – 515	Psi – 30000 , MPa – 205	40 %
SS 446	7.5 g/cm3	1510 °C (2750 °F)	Psi – 75,000 , MPa – 485	Psi – 40,000 , MPa – 275	20 %

Inconel vs stainless steel strength

Stainless Steel

Like plain steel, the term stainless steel can be applied to a wide variety of different alloys. A key characteristic of stainless steel is its protective oxide layer - which continuous exposure to extreme temperatures can damage.

There are many grades available in stainless steel, but let’s take a quick look at some of the most commonly used SS grades:

Grade 304 Stainless Steel. Resistant to oxidation damage at temperatures of up to 1,697°F (952°C). At 2,000°F, this alloy will experience significant loss of corrosion resistance and tensile strength.
Grade 316 Stainless Steel. While more resistant to chemical corrosion at room temperature than 304 SS, 316 SS is actually a bit less resistant to high temperatures than 304 is. At 2,000°F, this alloy loses even more tensile strength than 304 does.
Grade 330 Stainless Steel. This stainless steel alloy is specifically formulated to resist the effects of scaling and oxidation at high temperatures. The high chromium and nickel content of this alloy helps it withstand prolonged exposure to temperatures of up to 1,900°F (1037°C). Some might recommend it for use at 2,000°F, but at that point it’s usually better to use Inconel® instead.

Inconel vs stainless steel weight

Inconel alloy have lighter weight than stainless steel. Although the appearance of stainless and Inconel might be the same, the difference in weight is obvious.

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