How to Choose Alloys Based on Density and Melting Point?

When selecting alloys, you must pay attention to their density and melting point. Density determines the actual weight of the alloy. The melting point determines the limit service temperature of the alloy. They are the most important physical properties of alloys.

 

However, due to the complex composition of superalloys, the density and melting point of different superalloys vary greatly. In this article, we will summarize the density and melting points of Monel, Inconel, Incoloy and Hastelloy. It can be used as a better reference when you choose the alloy.

 

Density of Alloys

Density is an unavoidable physical quantity for calculating alloy weight. The weight of the material is obtained by multiplying the volume of the material by the density of the material. The most commonly used density units are g/cm³ (metric system) and lb/in³ (imperial system).

 

Alloy	Density		Alloy	Density
	lb/in³	g/cm³		lb/in³	g/cm³
Monel 400	0.318	8.8	Incoloy 890	0.287	7.94
Monel 401	0.321	8.91	Incoloy 903	0.298	8.25
Monel 404	0.322	8.91	Incoloy 907	0.301	8.33
Monel R-405	0.318	8.8	Incoloy 908	0.295	8.17
Monel K-500	0.305	8.44	Incoloy 909	0.296	8.19
Inconel 600	0.306	8.47	Incoloy 925	0.292	8.08
Inconel 601	0.293	8.11	Incoloy 926	0.29	8.03
Inconel 601GC	0.293	8.11	Incoloy 945	0.296	8.2
Inconel 602CA	0.29	7.93	Incoloy 945X	0.296	8.2
Inconel 603XL	0.308	8.54	Incoloy MA956	0.262	7.25
Inconel 617	0.302	8.36	Incoloy A-286	0.287	7.94
Inconel 625	0.305	8.44	Incoloy 020	0.292	8.08
Inconel 625LCF	0.305	8.44	Incoloy 028	0.29	8
Inconel 686	0.315	8.73	Incoloy DS	0.292	8.08
Inconel 690	0.296	8.19	Incoloy 330	0.292	8.08
Inconel 693	0.28	7.77	Incoloy 25-6HN	0.29	8.02
Inconel 706	0.292	8.08	Incoloy 27-7MO	0.289	8.02
Inconel 718	0.296	8.19	Hastelloy B	0.334	9.24
Inconel 718SPF	0.297	8.22	Hastelloy B-2	0.333	9.22
Inconel 725	0.3	8.31	Hastelloy B-3	0.333	9.22
Inconel 740H	0.291	8.05	Hastelloy C-4	0.312	8.64
Inconel X-750	0.299	8.28	Hastelloy C-22	0.314	8.69
Inconel 751	0.297	8.22	Hastelloy C-22HS	0.314	8.69
Inconel MA754	0.309	8.55	Hastelloy C-276	0.321	8.89
Inconel MA758	0.294	8.14	Hastelloy C-2000	0.307	8.5
Inconel 783	0.282	7.81	Hastelloy G-3	0.294	8.14
Incoloy 800	0.287	7.94	Hastelloy G-30	0.297	8.22
Incoloy 800H	0.287	7.94	Hastelloy G-35	0.297	8.22
Incoloy 800HT	0.287	7.94	Hastelloy N	0.32	8.86
Incoloy 803	0.284	7.86	Hastelloy S	0.316	8.75
Incoloy 825	0.294	8.14	Hastelloy W	0.325	9
Incoloy 832	0.28	7.75	Hastelloy X	0.297	8.22
Incoloy 864	0.29	8.02

 

In addition to calculating weight, density can also be considered as a factor in material selection. In some applications, components need to be as light as possible. In this case, less dense alloys should be given priority.

 

Alloys have different densities at different temperatures. Therefore, the density generally referred to is the density at room temperature.

 

Melting Point of Alloys

The melting point refers to the temperature at which the alloy changes from a solid to a liquid when the temperature increases. This process is also called melting. The units of melting point are °C (metric) and °F (imperial).

 

Alloy	Melting Point		Alloy	Melting Point
	°F	°C		°F	°C
Monel 400	2370 ~ 2460	1300 ~ 1350	Incoloy 803	2490 ~ 2555	1365 ~ 1400
Monel 401	2370 ~ 2460	1300 ~ 1350	Incoloy 825	2500 ~ 2550	1370 ~ 1400
Monel R-405	2370 ~ 2460	1300 ~ 1350	Incoloy 864	2467-2539	1353-1393
Monel K-500	2400 ~ 2460	1315 ~ 1350	Incoloy 890	2388 ~ 2522	1309 ~ 1383
Inconel 600	2470 ~ 2575	1354 ~ 1413	Incoloy 903	2405 ~ 2539	1318 ~ 1393
Inconel 601	2480 ~ 2571	1360 ~ 1411	Incoloy 907	2440 ~ 2550	1335 ~ 1400
Inconel 601GC	2374 ~ 2494	1301 ~ 1368	Incoloy 908	2482 ~ 2571	1361 ~ 1410
Inconel 602CA	2444 ~ 2552	1340 ~ 1400	Incoloy 909	2540 ~ 2610	1395 ~ 1430
Inconel 603XL	2516 ~ 2552	1380 ~ 1400	Incoloy 925	2392 ~ 2490	1311 ~ 1366
Inconel 617	2430 ~ 2510	1332 ~ 1380	Incoloy 926	2410 ~ 2550	1320 ~ 1400
Inconel 625	2350 ~ 2460	1290 ~ 1350	Incoloy 945	2317 ~ 2510	1270 ~ 1377
Inconel 625LCF	2350 ~ 2460	1290 ~ 1350	Incoloy 945X	2317 ~ 2510	1270 ~ 1377
Inconel 686	2440 ~ 2516	1338 ~ 1380	Incoloy MA956	2700	1480
Inconel 690	2450 ~ 2510	1343 ~ 1377	Incoloy A-286	2500 ~ 2600	1370 ~ 1430
Inconel 693	2403 ~ 2493	1317 ~ 1367	Incoloy DS	2520 ~ 2590	1380 ~ 1420
Inconel 706	2434 ~ 2499	1334 ~ 1371	Incoloy 330	2520 ~ 2590	1380 ~ 1420
Inconel 718	2300 ~ 2437	1260 ~ 1336	Incoloy 25-6HN	2470 ~ 2560	1354 ~ 1404
Inconel 718SPF	2300 ~ 2437	1260 ~ 1335	Hastelloy B-3	2500 ~ 2585	1370 ~ 1418
Inconel 725	2320 ~ 2449	1271 ~ 1343	Hastelloy C-22	2475 ~ 2550	1357 ~ 1399
Inconel 740H	2350 ~ 2484	1288 ~ 1362	Hastelloy C-22HS	2475 ~ 2550	1357 ~ 1399
Inconel X-750	2540 ~ 2600	1393 ~ 1427	Hastelloy C-276	2415 ~ 2500	1323 ~ 1371
Inconel 751	2540 ~ 2600	1390 ~ 1430	Hastelloy C-2000	2422 ~ 2476	1328 ~ 1358
Inconel MA754	2550	1400	Hastelloy G-35	2430 ~ 2482	1332 ~ 1361
Inconel MA758	2507	1375	Hastelloy N	2375 ~ 2550	1300 ~ 1400
Inconel 783	2437 ~ 2565	1336 ~ 1407	Hastelloy S	2435 ~ 2516	1335 ~ 1380
Incoloy 800	2475 ~ 2525	1357 ~ 1385	Hastelloy W	2350 ~ 2510	1290 ~ 1375
Incoloy 800H	2475 ~ 2525	1357 ~ 1385	Hastelloy X	2300 ~ 2470	1260 ~ 1355
Incoloy 800HT	2475 ~ 2525	1357 ~ 1385

 

Most alloys are used in the solid state. If the alloy has a lower melting point, then it can only be used in a narrower temperature range. Of course, in practical projects, alloys are rarely used at temperatures near the melting point.

 

You may have noticed that the melting point is actually a temperature range. This is because the alloy does not melt all at once during the temperature rise. When the alloy reaches a certain temperature, it starts to melt. This temperature is called the initial melting temperature. As the temperature continues to increase, more and more parts of the alloy melt. Until a certain temperature, the alloy is completely melted. This temperature is called the full melting temperature.

 

In fact, the melting point of the alloy decreases with increasing pressure. Therefore, the melting point we generally refer to is the melting point at standard atmospheric pressure.

 

Curie Point of Alloys

The Curie point is also called the Curie temperature. It refers to the temperature at which the material transitions magnetically. The units of the Curie point are °C (metric) and °F (imperial).

 

Alloy	Curie Point		Alloy	Curie Point
	°F	°C		°F	°C
Monel 400	70 ~ 120	21 ~ 49	Incoloy 800	-175	-115
Inconel 600	-192	-124	Incoloy 800H	-175	-115
Inconel 601	-320	-196	Incoloy 800HT	-175	-115
Inconel 625	< -320	-196	Incoloy 825	< -320	< -196
Inconel 625LCF	< -320	-196	Incoloy 903	780 ~ 880	416 ~ 471
Inconel 706	< -109	< -78	Incoloy 907	750 ~ 850	400 ~ 455
Inconel 718	-170	-112	Incoloy 908	539	282
Inconel 718SPF	-170	-113	Incoloy 909	750 ~ 850	400 ~ 455
Inconel X-750	-225	-193	Incoloy 926	< -22	< -30
Inconel 751	-193	-125

 

 

Metal materials will lose their magnetism when the temperature rises. The temperature at which a metal loses its magnetism is the Curie point.

 

Different alloys have different Curie points. When the Curie point of the alloy is lower than room temperature, the alloy is not magnetic at room temperature. Conversely, alloys are magnetic at room temperature.

 

In some projects (such as electronic applications), it is required that the material is non-magnetic. In this case, the Curie temperature becomes an important consideration.