Hardened inserts

Today s conventional drill bit utilizes three revolving cones containing teeth or hardened inserts that cut into the rock as the bit is revolved. The teeth or inserts chip off fragments of the rock which are carried to the surface with the drilling fluid. The frag-... 

A specialized case of profile extrusion exists when coating wire. The wire is fed through a hardened insert in the center of the die at high speed and the plastic is extruded around it through a manifold or multiple ports. Most dies are subjected to very high internal pressures since the uncommon pressure of over 5,000 psi (35 MPa) is required. 

The mould clamping plate is subject to large surface pressures originating from the manifold pressure discs, and there is also a risk of seizure of the plate surface by the discs during thermal expansion of the manifold. It is therefore recommended that the clamping plate be made of toughened steel, or that hardened inserts be located in it (see Figure 4.61). 

Both sohd-solution hardening and precipitation hardening can be accounted for by internal strains generated by inserting either solute atoms or particles in an elastic matrix (11). The degree of elastic misfit, 5, produced by the difference, Ai , between the lattice parameter, of the pure matrix and a, the lattice parameter of the solute atom is given by... 

Ion implantation (qv) direcdy inserts nitrogen into metal surfaces. A carefully poHshed and cleaned metal surface at room temperature in a vacuum (-- 0.133 mPa (l-) m Hg)) can be directly implanted with 80-keV nitrogen ions (10) (see Metal surface treatments, case hardening). In an alternative synthesis, argon ions (Ar ) of 8 keV can be used to ionize gas-phase nitrogen to obtain the same results (17). 

Impression plasters are used to obtain an impression (or negative) of the hard and soft tissues of the mouth. The plaster slurry is placed in a tray, inserted into the mouth, pressed in place against the area in question, and held stiU until it hardens. 

Another expression for the hardening index A is obtained by inserting the stress rate relation in the form (5.4) into the expression for the loading func-... 

Typical AP-T (Armor-Piercing-Tracer) Artillery Projectile, such as used in 120-mm AP-T Separated Projectile M358, is shown in Fig 1-7. Its solid cylindrical body (called "slug" or "shot ), made of hardened steel, has a pointed nose, a flat base and two gilding metal rotating bands. A tracer is inserted in the cavity of the base. The nose of proj is covered with a metallic (such as of forged Al) windshield (also known as "ballistic cap" or false ogive"), which makes the... 

As barrier methods of protection are extremely effective at reducing the spread of STDs, researchers have been examining the possibility of new barrier products that women can use and thereby take control. To date the female condom has proved to be unpopular and has been described as both noisy and uncomfortable [121]. An alternative female condom is under development at the Universite Laval in Quebec, Canada, where researchers are currently in the process of developing a physical barrier in the form of an invisible condom. The invisible condom is a thermoreversible gel that hardens when inserted into the vagina or the rectum due to the increased temperature of the human body. The gel, which breaks down several hours after application, has been shown in laboratory studies to provide sufficient protection against herpes simplex virus (HSV) and HIV. Although the invisible condom will provide women with the autonomy to protect themselves, and it has the major disadvantage that is unlikely to go unnoticed by the user s partner. 

Invasive and noninvasive Raman probes are used. The requirements for an invasive or insertion probe are that it should be industrially hardened, have a high degree of chemical/corrosion resistance, and be able to withstand very high process temperatures and pressures. Raman probes can withstand up to 350°C and 200 bar pressures, and operate under highly corrosive condi-... 

Figure 3-1 Diamond anvil high-pressure cell, (a) Detail of diamond cell, (b) Side view, (c) Front view. A and B, parts of piston C, hardened steel insert D, presser plate E, lever G, screw H, calibrated spring. (Reproduced with permission from Ref. 1.)...

To insert a product it can be just immersed in a plastic liquid prior to the plastic hardening. The product could have fixed spider type supports or retractable pins or other features to support it when molten plastic is poured or injected around it. Another approach is to place the product on a layer of plastic that is partially polymerized in a mold cavity followed by applying a final layer that physically encloses it. For certain plastics and/or products a vacuum system can be used if air pockets or voids are to be eliminated. 

When tool steels of high hardness are used they are supplied in the soft annealed condition (hardened mold inserts for cores, cavities, other molding surfaces and gibs, wedge locks, etc are typically hardened to a... 

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