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HQ 951154

JUNE 26 1992

CLA-2:CO:R:C:M 951154 JAS


TARIFF NO.: 8409.99.91, HTSUS

Ms. Sue S. Wilkerson
Cummins Engine Company, Inc.
Box 3005
Columbus, IN 47202-3005

RE: Cylinder Block Casting; Diesel Engine Block; Engine Block Casting; Rough Gray Iron Casting; Parts of Internal Combustion Diesel Engines; Subheading 8409.99.10; Advancement Beyond Cleaning; Stress Relieving; Other Parts; Subheading 8409.99.99

Dear Ms. Wilkerson:

In your letter of February 7, 1992, you inquire as to the tariff status of certain cylinder block castings from Brazil. Blueprints and drawings were submitted. Our ruling follows.


The articles in issue are described as rough, gray iron cylinder block castings for use in the manufacture of diesel engines. Metal foundries produce these castings as follows: pig iron, steel and other metals in small amounts, in the form of scrap, machining swarf, pit cast, and in-house reserves, are reduced to molten gray iron in coke fired cupolas and electric furnaces. This molten metal is poured into mold cavities and allowed to harden. The castings are then removed by a shakeout machine. These castings conform to a material specification outlining chemical composition, mechanical properties, microstructure, etc. It is apparent that iron predominates by weight over any other base metal constituent.

You state that internal stresses are reduced when castings are left to cool very slowly in the mold so that the thick and thin sections cool at approximately the same rate. However, to maximize mold utilization and overall production capacity some companies remove their castings from the mold prematurely and allow them to air cool. This causes residual stresses to
develop which makes the castings unacceptable for use in diesel engines. To relieve these stresses, the castings are placed in a furnace at 400-650 degrees F. The temperature is gradually increased to 1000-1150 degrees F and the castings held at this temperature for one hour per inch of thickness based on the heaviest section of the casting. They are then control cooled back to the original temperature at a rate not to exceed 250 degrees F per hour. After this heat treatment the castings are surface finished by some combination of chipping, grinding and sand blasting.

You state that these cylinder block castings are currently classified under the provision for other parts suitable for use solely or principally with the engines of heading 8407 or 8408, in subheading 8409.99.99, Harmonized Tariff Schedule of the United States (HTSUS). You maintain they should be classified in subheading 8409.99.10, a duty-free provision for other cast-iron parts not advanced beyond cleaning, and machined only for the removal of fins, gates, sprues, and risers.


Whether stress relieving is an advancement beyond cleaning for purposes of subheading 8409.99.10.


Merchandise is classifiable under the Harmonized Tariff Schedule of the United States (HTSUS) in accordance with the General Rules of Interpretation (GRIs). GRI 1 states in part that for legal purposes, classification shall be determined according to the terms of the headings and any relative section or chapter notes, and provided the headings or notes do not require otherwise, according to GRIs 2 through 6. GRI 6 states in part that for legal purposes, the classification of goods in the subheadings of a heading shall be determined according to the terms of those subheadings and any related subheading notes and, by appropriate substitution of terms, to GRIs 1 through 5, on the understanding that only subheadings at the same level are comparable. For the purposes of Rule 6, the relative section, chapter and subchapter notes also apply, unless the context requires otherwise.

Initially, the Explanatory Notes (ENs) constitute the Customs Cooperation Council's official interpretation of the Harmonized System and are useful in ascertaining the classification of merchandise under the System. Relevant ENs at p. 1152 indicate that, with certain exceptions not relevant here, heading 8409 covers parts of internal combustion piston engines
of heading 8407 or 8408 (e.g., pistons, cylinders and cylinder blocks, cylinder heads, cylinder liners, etc.). Therefore, the cylinder block castings are considered to be parts of heading 8409.

In the as-cast state, most castings are relatively brittle and possess poor mechanical properties. To render them serviceable they must be subjected to a variety of heat treatments designed to refine the grain, relieve internal stresses and develop the desired physical and mechanical properties. One such heat treatment is stress relieving. Unlike other heat treatments such as annealing and quenching and tempering, which you argue are clearly advancements in the as- cast articles, stress relieving temperatures are not high enough to alter the microstructure or mechanical properties of the castings. You state the process merely "re-creates" the normal aging process that would occur had the castings been allowed to cool in the mold.

The term stress relieving is defined in the Babcock and Wilcox text Guide to Steel Tubing Terminology as "a heat treatment which reduces the internal stresses that have been induced by casting, quenching, welding, cold working, etc." The USX (formerly United States Steel) publication The Making, Shaping and Treating of Steel, 10th. Ed., and similar publications are in accord. Noting this definition, in conjunction with the casting process you have described, we conclude that stress relieving is not a required step in the production of all merchantable gray cast iron castings, but only those that have been prematurely removed from the mold. From the record it appears that stress relieving is not commercially regarded as an integral part of the casting process. It is a process performed subsequently to improve the quality of a casting.

The classification of the instant cylinder block castings in one of the remaining applicable subheadings of heading 8409 depends on the principal use in the United States of the class or kind to which they belong. See Additional U.S. Rule of Interpretation 1(a), HTSUS. In a related ruling (HQ 951990, dated June 17, 1992), to your company, we held that based on the available evidence of principal use, certain diesel engine cylinder heads were classifiable in subheading 8409.99.91, HTSUS, a provision for parts suitable for use solely or principally with the engines for vehicles of subheading 8701.20, or heading 8702, 8703 or 8704.


Under the authority of GRI 1, applied at the subheading level through GRI 6, gray iron cylinder block castings that have been stress relieved are considered advanced beyond cleaning for purposes of subheading 8409.99.10, HTSUS.

The instant castings are classifiable in subheading 8409.99.91, HTSUS, a provision for other parts suitable for use solely or principally with the engines of heading 8407 or 8408. The column 1 rate of duty is 3.7 percent ad valorem. Articles from Brazil classifiable in this provision are eligible for free entry under the Generalized System of Preferences (GSP), upon compliance with the law and any applicable regulations.

This classification is based on the best evidence available to us at this time. Additional evidence of principal use that comes to our attention may cause us to reconsider our position.


John Durant, Director
Commercial Rulings Division

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