NS338

HuaNickel NS338 alloy came out in 1982, which is an improvement and development of the aforementioned high-molybdenum Ni-Cr-Mo alloys. The newly developed NS338 alloy system increases the chromium content by approximately 21% and reduces the amount of molybdenum by approximately 13%, and an appropriate amount of tungsten (approximately 3%) is added to balance the amount of chromium, molybdenum, and tungsten in the alloy. Because of these characteristics, the corrosion resistance of NS338 alloy is better than that of the Ni-Cr-Mo(- W) alloys mentioned above in many media. In particular, it is more obvious in oxidizing media such as FeCl₃ and CuCl₂, wet chlorine, and redox acids. At the same time, the alloy still has excellent resistance to pitting, crevice corrosion and stress corrosion.

NS338Chemical composition：

	Ni	Cr	Mo	W	Fe	C	Si	Mn	P	S	V
Min	Bal	20	12.5	2.5	2	≤
Max		22.5	14.5	3.5	6	0.015	0.08	0.5	0.04	0.02	0.35

NS338Physical properties：

Relative density	Melting point/℃		Specific heat capacity/J·(kg·K)-1					Thermal conductivity/W·(m·K)-1
			52℃		100℃		200℃	48℃		100℃	200℃	300℃
8.69	1359-1399		414		423		444	10.1		11.1	13.4	15.5
Resistivity/μΩ ·m						Linear expansion coefficient/×10-6m·(m·K)-
24℃		100℃		200℃		24～93℃			24～204℃		24～316℃
1.44		1.23		1.24		12.4			12.4		12.6

NS338Mechanical properties：

AlloyPlateSize	Welding method	trialTemperature/℃	σb/MPa	σp0.2/MPa	δ/%
Sheet thickness3.2mm	GTAW	room temperature 538	745 543	119 274	30 23
Medium plate thickness6.4mm	GTAW	room temperature 538	800 610	386 245	60 51
	GMAW(Short Arc)	room temperature 538	767 586	396 265	43 46
Medium plate thickness12.7mm	GTAW	room temperature 538 760	788 590 489	451 312 269	47 52 30
	GMAW(Short Arc)	room temperature 538 760	749 562 437	435 308 266	38 38 25
	GMAW(散弧)	room temperature 538 760	756 555 470	461 321 282	37 33 27

NS338Alloy properties：

Corrosion resistance: The alloy has good corrosion resistance in acetic acid, 10% FeCl₃, formic acid, extracted phosphoric acid, and some concentrations of sulfuric acid. Stress corrosion at 20 . In 4%MgCl₂, NS338 alloy has good chloride stress corrosion resistance after one week test.

Test conditions	204℃	232℃	Hardness
Solid solution	No cracking	No cracking	83HRB
20%Cold working	No cracking	No cracking	33HRC
50%Cold working	No cracking	No cracking	43HRC

NS338Uses of alloys：

HuaNickel NS338 is a relatively new corrosion-resistant alloy. It is mainly used in seawater, acetic acid, acetic anhydride, chlorination and hydrogen fluoride systems, pickling equipment for phosphoric acid and mixed acid production, plate heat exchangers, SO cooling towers and other applications to solve problems such as total corrosion, pitting corrosion, and crevice corrosion.

NS338Process performance：

Welding process: welding performance

NS338 alloy has good weldability, and can be welded by the general welding methods of the above-mentioned high nickel-chromium-molybdenum alloys, such as GTAW, GMAW, SMAW, etc.

Heat treatment: After cold and hot processing, NS338 alloy is treated with a solid solution treatment process of quenching after heating and heat preservation at 1120°C.

Relevant standards：

SB 575/B 575、 SB 574/B 574 、B 472、SB 622/B 622、 SB 619/B 619

SB 626/B 626、SB 366/B 366 、SB 462/B 462 、SB 564/B 564 、SB 462/B 462