Introduction of Our New Grade 17-4PH

Introduction of Our New Grade 17-4PH

17-4PH Stainless Steel

UNS S17400 | AMS 5643 | ASTM A564 | ASTM A693 Grade 630

17-4PH Stainless Steel is the most widely used steel of the precipitation hardening grade steels. It has high toughness, strength, and corrosion resistance. Typical usage is seen in applications requiring high strength and a modest level of corrosion resistance. Strength and toughness desired can be manipulated by temperate range in the heat treatment process.

Chemical Composition

Element	Content(%)
Iron, Fe	73
Chromium, Cr	15.0-17.5
Nickel, Ni	3.0-5.0
Copper, Cu	3.0-5.0
Manganese, Mn	1.0
Silicon, Si	1.0
Tantalum, Ta	0.45
Niobium, Nb (Columbium, Cb)	0.45
Nb + Ta	0.15-0.45
Carbon, C	0.070
Phosphorous, P	0.040
Sulfur, S	0.030

Physical Properties

Properties	Metric	Imperial
Density	7.75 g/cm³	0.280 lb/in³

Mechanical Properties

Properties	Metric	Imperial
Shear modulus	77.4 GPa	11200 ksi
Elastic modulus	190-210 GPa	27557-30458 ksi
Poisson's ratio	0.27-0.30	0.27-0.30
Hardness, Brinell	352	352
Hardness, Knoop (estimated from Rockwell C)	363	363
Hardness, Rockwell C	36	36
Hardness, Vickers (estimated from Rockwell C)	349	349

Thermal Properties

Properties	Metric	Imperial
Thermal expansion co-efficient (at 21-93°C/69.8-199°F)	10.8 µm/m°C	6.00 µin/in°F
Thermal conductivity ( for condition H 900 at 149ºC. 22.6 W/mK for H 900 at 482ºC)	17.9 W/mK	124 BTU in/hr.ft².°F

Fabrication and Heat Treatment

Machinability

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Grade 17-4ph stainless steel can be machined in the annealed condition. This alloy has long and gummy chips. Before final hardening, post machining solution treatment is needed if it is machined in the H1150M condition.

Forming

Grade 17-4ph stainless steel can be formed mildly.

Welding

Grade 17-4ph stainless steel can be welded using common fusion and resistance welding methods. Oxyacetylene welding method is not preferred for welding this alloy.

Heat Treatment

Grade 17-4ph stainless steel is soaked at 1038°C (1900°F) for 30 min and cooled below 16°C (60°F) for complete martensite transformation in the condition A. The condition A material is treated at 482°C (900°F) for 1 h followed by cooling. Solution treated material is soaked for 4 h at specific temperature in H925, H1025, H1075, H1100, and H1150 conditions followed by cooling in air.

Solution treated material is soaked at 760°C (1400°F) for 2 h in the H1150M condition followed by cooling. It is again heated at 620°C (1150°F) for 4 h followed by cooling.

Forging

Grade 17-4ph stainless steel is forged at 1010°C (1850°F). Before performing this process, it is soaked at 1177°C (2150°F). Post-work solution treatment should be performed before final hardening.

Hot Working

Grade 17-4ph stainless steel can be hot worked using common processes. It is treated at 1038°C (1900°F). Post-work solution treatment should be performed before final hardening.

Cold Working

Grade 17-4ph stainless steel can be cold worked using common techniques in spite of its high initial yield strength.

Annealing

Grade 17-4ph stainless steel is annealed at 1038°C (1900°F) for 0.5 h followed by cooling rapidly.

Hardening

Grade 17-4ph stainless steel has high ductility, and can be formed using all conventional techniques. Powerful equipments are required for forming this alloy because it is stronger than the regular steel. Heavy-duty lubricants are used during cold working.

Applications

Grade 17-4ph stainless steel is used in the following applications:

·Nuclear reactor

·Aircraft and gas turbines

·Oil field

·Chemical process components

·Paper mill