AMS 5772 Haynes 188 Bar

 

Haynes 188 (UNS R30188, W.Nr. 2.4683) is a solid-solution-strengthened cobalt-nickel-chromium-tungsten-based alloy. A unique feature of this material is the trace element lanthanum (La)-a 0.03% lanthanum content constitutes the "exclusive formula" of Alloy 188.

 

Based on our years of experience working with this material, our strongest impression is this: it is the "champion of oxidation resistance" among cobalt-based alloys. While other materials may completely shed their oxide scales at 1093°C, Alloy 188 retains its protective layer. The AMS 5772 standard serves as the production specification for Alloy 188 in the form of bars, forgings, and rings; it is typically utilized in aerospace applications such as fasteners, turbine disks, and structural support components.

 

 

What makes the Haynes 188 "more heat-resistant than the competition"?  There are 7 key reasons:

 

1. Lanthanum (0.03–0.12%) - Alloy 188's "Exclusive Formula."
Simply put, while the oxide scale on other alloys tends to flake off at temperatures above 1000°C at the slightest touch, the oxide scale on Alloy 188 is "grown" onto the substrate-it does not detach. This is the specific function performed by that tiny fraction (a few hundredths of a percent) of lanthanum.

2. Cobalt Base - The Foundation for Hot Corrosion Resistance
With a cobalt content of approximately 37–39%, Alloy 188 possesses an inherent resistance to sulfide and chloride-induced hot corrosion-such as that found in low-grade fuel combustion environments or saline conditions (e.g., marine applications)-that is superior to that of nickel-based alloys.

3. Tungsten (14–16%) + Chromium (21–23%) - A One-Two Punch of Solid Solution Strengthening
This specific combination enables Alloy 188 to maintain stable performance at temperatures up to 1095°C.

4. Solid Solution Strengthening - No Aging Treatment Required; Ready for Use Immediately After Welding

5. Low-Temperature Toughness - Serviceable Even at -185°C
A frequently overlooked feature of Alloy 188 is its impressive low-temperature impact strength: even at -185°C, its impact energy remains as high as 158 joules. This demonstrates its robust resistance to low-temperature impact loading. If you require a metallic material for use in polar environments or equipment operating at liquid nitrogen temperatures, Alloy 188 is an excellent choice.

6. Intermediate-Temperature Embrittlement (650–870°C) - A Potential Pitfall That Must Be Clearly Addressed Upfront
When subjected to prolonged "baking" within the 650–870°C temperature range, Alloy 188 will gradually become brittle. If your components are intended for long-term service within this specific temperature window, periodic inspections are strongly recommended.

 

7. Prohibited Use Cases-This, too, must be clearly specified.

Alloy 188 is susceptible to reducing atmospheres (such as hydrogen and carbon monoxide), as the protective oxide film is destroyed in such environments. It is also vulnerable to contamination by low-melting-point metals (such as copper, aluminum, and zinc); at high temperatures, these metals can penetrate along the grain boundaries, leading to embrittlement. If your operating conditions involve these factors, then this material is not suitable.

 

The seven characteristics outlined above keep the global market price of Haynes 188 alloy consistently high; its pricing tracks closely with the markets for cobalt, nickel, and tungsten, resulting in significant volatility. Furthermore, processing costs are substantial-the machining cost for Haynes 188 is approximately three to five times that of stainless steel. Moreover, materials meeting the aerospace standards AMS 5772, AMS 5608, and AMS 5801 require custom production, meaning there is virtually no readily available stock on the open market.

Customization Consultation

 

 

 

(UNS R30188 / AMS 5772)

 

	C	Mn	Si	P	S	Cr	Ni	W	La	B	Fe	Co
Min	0.05	-	0.20	-	-	20	20	13	0.02	-	-	-
Max	0.15	1.25	0.50	0.02	0.015	24	24	16	0.12	0.015	3	Bal

 

 

(AMS 5772 Bar, Solution-Treated Condition)

 

	Yield Strength (0.2%)	Tensile Strength	Elongation	Hardness
	MPa	MPa	4D	HB
Bars	≥379 MPa (55 ksi)	≥862 MPa (125 ksi)	≥30%	≤302

 

 

This is a characteristic of Haynes 188: while it offers relatively good machinability for a cobalt-based alloy, it is significantly more difficult to machine than stainless steel. We want to make this point clear up front to anyone considering purchasing this material.

 

1. Hot Working - Narrow Temperature Window; Precise Temperature Control Required

When hot working Alloy 188, the temperature must be raised above 1175°C; working at lower temperatures will result in cracking. Much like L605, it is a demanding material to handle.

2. Cold Working - Rapid Work Hardening; Intermediate Annealing Required

3. Welding - Mature Process; Post-Weld Heat Treatment Generally Not Required

4. Heat Treatment - Solution Treatment is a Critical Step and Cannot Be Omitted

The performance of Alloy 188 is highly dependent on solution treatment. We typically supply the material in the solution-treated condition.

Recommendations for Condition Selection:

• For applications requiring extensive machining or welding → Solution-treated condition
• For structural components requiring higher strength,h → Cold working followed by aging treatment is an option; however, please note the resulting reduction in ductility.

 

5. Machining - More Difficult than Stainless Steel; Proper Preparation is Essential
During the machining of Alloy 188, cutting-edge temperatures become extremely high; therefore, adequate cooling is absolutely critical. Machining costs are approximately 3 to 5 times higher than those for stainless steel; when preparing a quotation, we will factor this cost into the calculation based on your specific requirements.

 

 

Before we provide you with a formal quotation, discussing these fundamental questions regarding AMS 5772, Haynes 188, and Bard will help expedite our quoting process:

Forms: Round Bar, Square Bar, Hexagonal Bar, Forgings (Rings, Discs)

Dimensions: Typical Diameter 10–300 mm; Length ≤ 6000 mm

Condition: Solution-Treated (Standard Delivery Condition)

Surface Finish: Black, Turned, Ground

Melting Process: Is a dual-vacuum process (VIM+VAR) required? Typically required for aerospace applications.

 

Note: Our past clients in the aviation sector have consistently undertaken extensive material prototyping and rigorous testing-involving multiple rounds of sampling-to ensure that any potential issues are fully resolved before formal procurement. If you are also an aerospace industry professional in need of materials for testing purposes, please do not hesitate to contact us.

Get a Quote

Hot Tags: ams 5772 haynes 188 bar, China ams 5772 haynes 188 bar manufacturers, factory