Machined 304 stainless steel

Figure 4.28 Overview of the five machined stainless steel plates. Two possible arrangements of all these system parts are given as well many other are possible due to a flexible interconnection concept [56].

The ion pump is widely used in all-metal systems, which are usually fabricated of stainless steel with copper gaskets between machined stainless-steel flanges. With the ion pump in operation, these systems can be baked out for several hours at 250°C (or even as high as 400°C) to desorb surface gases (mainly water). The ion pump can be baked out at the same time, but its temperature should not exceed 250°C (to protect the magnet). 

Screws, round head machine, stainless steel, 6-32x 1 [Pg.195]

Bargel H-J, Schulze G (1994) Werkstoffkunde [Materials engineering]. VDI Verlag, Diisseldorf (in German) Belejchak P (1997) Machining stainless steel. Adv Mater Process 152(6) 23-25... 

Free-machining stainless steels are unweldable because of their high sulphur content. 

Injection molds are machined from a variety of tool steels and then hardened or in some cases plated with chromium, nickel, or proprietary materials. Large molds use prehardened tool steels because they cannot be hardened after machining. Stainless steel is used for some smaller molds, particularly those used for optical and medical parts and for corrosion resistance. Because they provide better heat transfer and thus shorter molding cycles, materials such as beryllium copper are used as inserts in critical areas. 

The following steps should be followed when passivating free-machining stainless steels with the... 

Testing is often performed to evaluate the passivated surface. For example, 400 series, precipitationhardening, and free-machining stainless steels are often tested in a cabinet capable of maintaining... 

Tellurium improves the machinability of copper and stainless steel, and its addition to lead decreases the corrosive action of sulfuric acid on lead and improves its strength and hardness. Tellurium is used as a basic ingredient in blasting caps, and is added to cast iron for chill control. Tellurium is used in ceramics. Bismuth telluride has been used in thermoelectric devices. 

Ytterbium metal has possible use in improving the grain refinement, strength, and other mechanical properties of stainless steel. One isotope is reported to have been used as a radiation source substitute for a portable X-ray machine where electricity is unavailable. Few other uses have been found. 

A method for the fractionation of plasma, allowing albumin, y-globulin, and fibrinogen to become available for clinical use, was developed during World War II (see also Fractionation, blood-plasma fractionation). A stainless steel blood cell separation bowl, developed in the early 1950s, was the earhest blood cell separator. A disposable polycarbonate version of the separation device, now known as the Haemonetics Latham bowl for its inventor, was first used to collect platelets from a blood donor in 1971. Another cell separation rotor was developed to faciUtate white cell collections. This donut-shaped rotor has evolved to the advanced separation chamber of the COBE Spectra apheresis machine. 

Fig. 10. Schematic of casting machine used to make microporous membranes by watervapor imbibition. A casting solution is deposited as a thin film on a moving stainless steel belt. The film passes through a series of humid and dry chambers, where the solvent evaporates from the solution, and water vapor is absorbed from the air. This precipitates the polymer, forming a microporous membrane that is taken up on a collection roU (25).

Depth-of-Gut Notching. Depth-of-cut notching (DOCN) is a localized wear process common when machining materials such as austenitic stainless steels or high temperature alloys. Notching is attributed to the chemical reaction of the tool material and the atmosphere, or to abrasion by the hard, sawtooth outer edge of the chip. DOCN may lead to tool fracture. 

Martensitic Stainless Steels. The martensitic stainless steels have somewhat higher carbon contents than the ferritic grades for the equivalent chromium level and are therefore subject to the austenite—martensite transformation on heating and quenching. These steels can be hardened significantly. The higher carbon martensitic types, eg, 420 and 440, are typical cutiery compositions, whereas the lower carbon grades are used for special tools, dies, and machine parts and equipment subject to combined abrasion and mild corrosion. 

Dyeing can also be carried out ia hide processors or automatic stainless steel dyeiag machines with a Y-shaped cross sectioa to subdivide the iaterior iato three loading sectioas, somewhat similar to a large-scale washiag machine. 

In addition, the magnetic characteristics of a material can change as a function of stress (e.g., unannealed series 316 stainless steel can be magnetic after machining), temperature, pressure, and physical and chemical treatment. Therefore, when two paramagnetic materials with similar magnetic susceptibilities are to be separated, the possibility that pretreatment will facilitate subsequent separation should be studied. 

Drum construction is typically of carbon or stainless steel when treating granular materials minus 1 mm in size. Drum diameter has ranged from 0,150 to 0,360 rn, while drum length v aries from 0,460 to 3,050 rn in industrial ion-bornbardrnent (high-tension) machines. 

Figure 2.17 Pitting at a free-machining austenitic stainless steel threaded valve throat. The valve controlled flow of a chlorine-containing, low-pH biocide.

While detail may be found in the ASTM D-3330 or PSTC-1 and PSTC-2 standards, the peel test is typically carried out as follows The tape is conditioned at 23°C and 50% relative humidity for 1 day. Next, the tape is rolled down with a weighted standard roller onto a clean test substrate (usually polished 302 stainless steel), allowed to dwell for a specified time (usually 1 min), and then clamped with the testing fixture in the test machine and peeled at a specified rate. 

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