OCETA ENVIRONMENTAL TECHNOLOGY PROFILES Deep Drawn and Ironed Cylinders and Pressure Vessels CAT. # 08-021 / 12-002 CONTACT: DDI Seamless Cylinder International Inc. 1667 Trunk Road Sault Ste. Marie Ontario, Canada P6A 6X9 Tel. (705) 759-0060 Fax (705) 759-0063 Email: sales@seamlesscylinder.com Website: www.seamlesscylinder.com

PROCESS/ PRODUCT DESCRIPTION: pressure vessels cylinders shells housings tight geometric tolerances high length/ diameter ratios high strenth smooth finish DDI Seamless Cylinder International Inc. specializes in the manufacture of deep drawn and ironed (DDI) components. Primary products are closed ended, cylindrical steel pressure vessels (Figure 1). The pressure vessels are manufactured in a variety of sizes and strengths specific to their application. For general industry use, DDI Seamless Cylinder currently produces pressure vessel cylinders of up to 1000 cubic inches in capacity. The DDI process achieves inside diameters of 2 - 7" and lengths up to 24", within length to diameter ratios of up to 4:1 (Table 1). The ironing process provides a smooth surface finish and tight geometric Figure 1: Various Closed-Ended Shells tolerances. DDI parts are economical in applications where final machining would normally be required. High strength and fine grain structure are innate enhancements of the severe cold working of the DDI process. Tensile and yield strengths of more than 100,000 P.S.I. and 90,000 P.S.I., respectively, are achieved in HS LA steel. The destructive burst failure mode is ductile with no fragmentation.

PROCESS/ PRODUCT APPLICATION: fire extinguishers acetylene cylinders filter housings automotive air bag inflators air reservoirs gas bottles DOT 4B, DOT 39, DOT 8AL, UL 299 cylinders Pressure vessels are used in the safe storage, dispensing and transfer of liquids, powders and gases. They are used in a variety of applications including automotive air bag systems, filter housings, fire extinguishers and high-pressure gas cylinders (Figures 2 and 3). UL, TC and the US DOT standards regulate their design and manufacture. Pressure vessels produced using the DDI process are used in applications where high quality, strength and geometric consistency are a must.

PROCESS/ PRODUCT OPERATION: deep draw and iron cylinder forming mild steel trim to length hole piercing MIG welding pneumatic proof testing powder paint coating stamping press multi-spindle lathe	The deep draw and iron (DDI) process is a cold forming method, which significantly enhances the properties of mild steel. In this process, flat circular steel blanks are loaded into a hydraulic press. A cylindrical draw punch contacts the blank and pushes it through an intake ring. As the blank is pushed through this ring, it is formed into a thick-walled cylindrical cup. The punch continues its motion in the same direction, pushing the cup through a series of progressively smaller diameter ironing dies. As the cup passes through these dies, the outside diameter is reduced, resulting in the thinning or "ironing" of the sidewall of the cup transforming the cup into a much longer cylindrical shell. The shell is stripped off the punch on the return stroke of the press. The shell can be loaded into a second toolset and the ironing process can be repeated resulting in an even longer, thinner-walled shell. In line cut off machines trim the shells to length. Cycle times vary with part size and severity of draw and range from 40-500 parts per hour. DDI presses can easily be tooled for different lengths and diameters and are well suited for long production runs. In addition to three DDI press lines, which form shells such as components for air bag system inflators, bottled gas cylinders and other open-ended housings, the company also completes its DDI shells as pressure vessels for specific markets such as fire extinguishers and filtration products. Automated MIG welders are used to produce pressure vessels by welding base closures in the open end	Figure 2: Welded Pressure Vessels Figure 3: Deep Drawn and Ironed Steel Shell

and threaded fittings to the closed end of the cylinder shells (Figure 3). Pneumatic test chambers are used to leak test each vessel, as required by product regulations. The vessels are then either packaged for shipment or transferred to the conveyorized, multi-stage washer and electrostatic powder paint line for finishing. The powder coating line includes a modular booth to allow for custom paint finishes, in addition to the standard red colour used for fire extinguisher products. A wide range of support equipment augments the main shell forming and finishing lines. Custom threaded fittings are manufactured in-house using a multi-spindle lathe. A stamping press is used to produce the shell base closures from steel coil. Low tonnage presses are used to text stamp regulated and serialized products. The quality control facilities include high-pressure hydrostatic burst and permanent expansion equipment, a hardness tester, optical comparator and standard metrology equipment.

VENDOR INFORMATION: DDI Seamless Cylinder International Inc. www.seamlesscylinder.com

DDI Seamless Cylinder was established in 1981 and initially produced pressure vessels for the fire extinguisher industry. Production has grown to include automotive air bag

inflator bodies, gas bottle shells, filter housings and various accumulators and dispensing bottles. The company will adapt standard tooling or develop unique tooling to meet

custom requirements. DDI Seamless Cylinder exports the majority of its products to the United States and several overseas countries.

This document was originally published February, 2000. It is best viewed with the font Times, size 12. While OCETA has reviewed this product/process with the Vendor and conducted limited independent investigation, OCETA assumes no responsibility for the accuracy and completeness of the information.

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