Abstract: A seamless steel-body cylinder, suitable for storing ultra-high purity gases, has an inert metal lining. The cylinder lining is preferably nickel and completely covers the interior surface of the steel cylinder body, preventing the stored gas from making any contact and reacting with the steel cylinder body. The surface of the inert metal lining is conditioned to be smooth, preferably to 15 R.sub.a or better. The cylinder body is preferably externally threaded to secure end closure devices to the cylinder body.

Abstract: An apparatus for the field milling of a pocket into a railroad stock rail to accommodate the precise nesting abutment of a switch point rail thereto avoids the necessity of milling such pockets under shop conditions and permits the use of Continuous Welded Rail (CWR) through railroad switches. The portable, self-propelled apparatus is adapted to the field milling of pockets into stock rails to accept the selectable placement of a movable switch rail therein and is powered by a portable power supply that may be either auxiliary or integral. The apparatus comprises components which are preferably fluid-powered. The apparatus clamps onto the stock rail and comprises a positionable milling assembly inclined at the angle necessary for milling the desired pocket into the stock rail. The apparatus moves the apparatus along the stock rail at a controlled speed whereby the milling head is fed along the stock rail during the milling operation.

Abstract: The invention relates to free-machining steels which do not rely on lead as a means of enhancing machinability. Instead, the steels of the invention employ concentrations of tin at ferrite grain boundaries to replicate a role of lead, which the inventors have discovered, in enhancing machinability. This role is to cause an embrittlement at the localized cutting zone temperatures by changing the fracture mode from transgranular to intergranular at those temperatures. The invention's use of concentrations of tin at the ferrite grain boundaries of the steel permits the machinability-enhancing effect to be obtained while employing bulk tin contents below the levels at which hot tearing becomes problematic. The invention improves over lead-bearing, free-machining steels in that the machinability-enhancing embrittlement produced by concentrating tin at the ferrite grain boundaries is both controllable and reversible.