(ii) Taper threads to be of length not below as specified for American Standard taper pipe threads.
The material has to be discovered by any suited system apart from that plates and billets for hot-drawn cylinders should be marked with the warmth selection.
(iii) When sizing of cylinder doesn't permit securing straight specimens, the specimens could be taken in almost any locale or route and will be straightened or flattened cold by tension only, not by blows.
(ii) One particular cylinder need to be picked from Each individual large amount and become hydrostatically force tested to destruction. If this cylinder bursts below five (five) situations the provider strain, then two further cylinders from your same large amount as the Beforehand analyzed cylinder should be picked and subjected to this exam.
(i) The phrase “spun” or “plug” needs to be placed near the DOT specification marking when an end closure within the finished cylinder has actually been welded with the spinning procedure, or effected by plugging.
Cylinders has to be manufactured working with machines and procedures enough to ensure that Each and every cylinder generated conforms to the necessities of the subpart. No fissure or other defect is permitted that is likely to weaken the concluded cylinder appreciably. A fairly smooth and uniform area finish is required. Otherwise at first absolutely free from such defects, the surface area could be machined or in any other case addressed to reduce these defects.
(iv) Lasting volumetric enlargement may well not exceed 10 % of the whole volumetric growth at test tension.
Reheat cure is approved for a rejected cylinder in accordance using this paragraph (n). Immediately after reheat procedure, a cylinder will have to move all prescribed checks During this portion to become regarded acceptable. Restore of brazed seams by brazing and welded seams by welding is approved.
(four) In the event the cylinder area will not be at first free of charge with the defects, the surface area could possibly be machined or if not addressed to eliminate these defects delivered the bare minimum wall thickness is preserved.
(four) As a safety precaution, if the maker elects to help make this exam here before the hydrostatic check, he should layout his equipment so the force is applied to the smallest spot practicable, across the issue of closure, and in order to make use of the smallest feasible quantity of air or gas.
(1) Marking on Every single cylinder have to be stamped plainly and forever on or close to the shoulder, prime head, neck or valve safety collar which happens to be permanently attached to your cylinder and forming integral part thereof.
Reheat treatment of turned down cylinders is approved. Subsequent thereto, cylinders have to move all prescribed exams to get suitable. Repair service by welding or spinning is not approved.
(6) Other markings are authorized provided These are designed in lower worry places apart from the facet wall and are not of the dimension and depth that should make dangerous stress concentrations. These marks may not conflict with any DOT demanded markings.
Cylinders must be made employing devices and procedures suitable to make sure that Every cylinder produced conforms to the requirements of this subpart and the subsequent: