K MONEL.doc

Vendor Acknowledgement of K-Monel Heat Review

Enclosure (2)

1. Recent investigations into mechanical property failures of fasteners manufactured from NiCuAI (K-Monel) material that was produced by Special Metals Corporation (formerly INCO Alloys) of Huntington, West Virginia has found eighty (80) heats of material which may not meet the mechanical property requirements of QQ-N-286 throughout the heat. In 1994, Special Metals Corporation implemented a process change that eliminated the addition of extra aluminum at the toe of each NiCuAl (K-Monel) ingot resulting in the toe’ portion of the heat being non-homogeneous in comparison to the rest of the heat. Due to cropping practices at Special Metals Corporation, material from the toe of the ingot with non-homogeneous aluminum content was not cropped from production material prior to shipment. A recent study has shown that the aluminum concentration in the toe portion of the ingot could be as low as approximately 2.0% with corresponding yield strength as low as approximately 40,000 PSI. QQ-N-286 specifies an aluminum content of 2.3% minimum and a yield strength of 90,000 PSI minimum or 85,000 PSI minimum for material = 1”. As a result of the investigation, the eighty (80) heats listed in Table I are considered suspect of having problems with insufficient aluminum content and an inability to consistently attain the required minimum yield strength.

2. You are requested to review your records of in stock and in process K-Monel material from the Special Metals Corporation for the suspect heat numbers listed in Table I below. You are prohibited from providing raw stock or finished products made from the suspect K-monel heats. If suspect heats are intended to be used, contact the PHNS & IMP contracting officer for adjudication of the material.

Table I - List of Suspect Special Metals Corporation K-Monel Heat Numbers

Additional ordering data: All slow strain rate tests used to satisfy the requirements of QQ-N-286G must be done by one of the approved laboratories listed below.

Vendor acknowledgement of K-Monel Heat Review attachment applies.

3.

The following laboratories have participated in the round robin of studies of this strain rate test discussed above, have a set of photographs illustrating grain boundaries that have intergranular fracture features, and have demonstrated their ability to do the slow strain rate test. All slow strain rate tests done to satisfy the requirements of ref. (c) must be done by one of the approved laboratories listed below:

Huntington Alloys, a Special Meta1~ Company

Attn:Frank Veltry

3200 Riverside Drive

Huntington, WV 25705

Phone:

(304) 526-5759

FAX: (304) 526-5973

Metallurgical consultants, Inc.

Attn: W. M. Buehler

4820 Caroline

P0 l3ox 88046

Houston TX 77288-0046

Phone:(713) 526-6351

FAX: (713) 526-2964

Naval Surface Warfare Center, Carderock

Attn: Eric Pocht

Code 614

9500 Macarthur Blvd

West Bethesda, MD 2083.7-5700

Phone: (301) 227-5032

FAX: (301) 227-5576

Teledyne Ailvac

Attn: Dr. W. D. Cao

2020 Ashcraft Ave.

Monroe, NC 28110

Phone: (704) 289-4511

Fax: (704) 289-4269

Mannesmann Rôhrenwerke

Mannesmann Porschungsinstitut (MPI)

Attn: Dr. Weiss

Postfach 251160

47251 Duisburg

Germany

Phone: 011-49-0203-9993194

Fax: 011-49-0203-9994415