Method of fabricating a high pressure tank

• US 4,364,161 A
• Filed: 12/29/1980
• Issued: 12/21/1982
• Est. Priority Date: 12/29/1980
• Status: Expired due to Fees

• Current Assignee: Marison Cylinder Co. (Enovis Corp.)
• Original Assignee: The Marison Company
• Inventors: Stading, Russell C.
• Primary Examiner(s): Combs, Ervin M.
• Application Number:
  US06/221,168
• Time in Patent Office: 722 Days
• Field of Search: 29/407, 29/446, 72/82, 72/83, 72/85, 73/49.3, 73/52, 73/587, 73/598, 73/801, 220/3, 228/103, 228/104, 228/155, 228/173 F, 413/1, 413/69
• US Class Current: 29/407.08
• CPC Class Codes: B21D 51/24 high-pressure containers, e.g. boilers, bottles
• CPC Class Codes: B23P 15/22 cartridges or like shells
• CPC Class Codes: Y10T 29/49776 Pressure, force, or weight determining

Abstract

A tank and method for fabricating the tank are disclosed wherein a longitudinally seam welded segment of a generally cylindrical steel tube is formed by hot spinning into a cylinder. The cylinder is heat treated, shot blasted, and non-destructively tested to verify that the heat treatment is uniform and proper, that the wall thickness is as desired, and that the weld region is acceptable with no critical defects created as a result of the hot spinning and heat treating. The cylinder is pressurized with air to a predetermined pressure to verify that there is no leakage from the spun closed end of the tank. Finally, the cylinder is hydrostatically tested to a predetermined pressure level with water and the cylinder weld is simultaneously examined by means of acoustic emission with the cylinder stressed in response to the internally applied hydrostatic test pressure to determine if a paste weld condition exists.

Claims

1. A method of fabricating and testing a tank for storing and transporting high pressure gases comprising the following steps:

(a) providing a steel strip formed into a substantially closed curve configuration with the longitudinal margins thereof in an aligned and adjacent relationship and effecting an electrical resistance seam weld along said adjacent margins to form a length of seam welded tubing;

(b) ultrasonically examining the weld region of the tubing for voids and lack of fusion to 5 percent of the tubing thickness;

(c) effecting a final forming of the tubing to a desired diameter and then subjecting the circumference of the finally formed tubing to a flux leakage test for flaws and critical defects;

(d) hydrostatically testing said tubing for paste-welding;

(e) hot spinning the finally formed tubing to form a tank with a cylindrical sidewall, a bottom, and a neck;

(f) heat treating said tank;

(g) shot blasting said tank;

(h) non-destructively testing said tank with ultrasonic and eddy current techniques to verify that the heat treatment is uniform and proper, that the wall thickness is as desired, and that the weld region continues to be acceptable with no critical defects created as a result of said hot spinning and said heat treating;

(i) spot facing the neck end of the tank, facing the neck to the desired length, turning the diameter for the neck ring when required, predrilling a hole through the neck, core drilling a bore in the neck for subsequent tapping, and tapping the formed bore;

(j) discharging steam into the tank with the tank in inverted position until the inside of the tank is clean and hot;

(k) vacuuming the inside of the tank until it is clean and dry;

(l) pressurizing the tank with air to a predetermined pressure to verify that there is no leakage from the spun closed end of the tank; and

(m) hydrostatically testing the tank to a predetermined pressure level with water and simultaneously examining the tank weld by means of acoustic emission with the tank stressed in response to the internally applied hydrostatic test pressure to determine if a paste weld condition exists.

2. A method for making and testing a tank suitable for use in storing and transporting gases at pressures at or above about 1800 psig, said method comprising at least the following steps:

(a) providing a length of welded steel tubing having a generally hollow cylindrical configuration which includes a generally linear weld region;

(b) hot spinning the tubing and forming said tubing into a tank having a bottom, a cylindrical sidewall, and a neck;

(c) heat treating said formed tank;

(d) non-destructively testing said tank with ultrasonic and eddy current techniques to verify that the heat treatment is uniform and proper, that the wall thickness is as desired, and that said weld region continues to be acceptable with no critical defects created as a result of said hot spinning and said heat treating; and

(e) hydrostatically testing the tank to a predetermined pressure level with liquid in accordance with applicable codes and simultaneously examining the tank weld by means of acoustic emission with the tank stressed in response to the internally applied hydrostatic test pressure to determine if a paste weld condition exists.