Steel containing boron

The chemical symbols refer to the percentage of the element in the steel, but this formula is not valid for low carbon low alloy steels containing boron, although it appears to work for higher carbon... 

The multiphase equilibrium technique using silver as the liquid phase was resorted to in Ref.153 but the details were not given. The 7S of stainless steel containing 0.001 —0.006% boron appeared to be near 880 erg/cm2 at 1050 °C, and the 71 again was unusually high, namely about 620 erg/cm2. 

Laser beam technologies can be applied with major efficiency during Nuclear Submarine (NS) dismantling operations for -cutting of metal constructions -welding of boron-containing-steel containers to store nuclear fuel and -decontaminating NS units and assemblies. 

Complex carbides containing boron, occurring frequently in boron-alloyed steels and superalloys, are also named carboborides. Metal borocarbides (see Table 1) are synthesized by powder metallurgical methods or are extracted from a metal matrix. There are pseudoternary or -quaternary borocarbides, such as Mn23(B, C) or (Cr, Mn, Fe)23 (B, C)g (t phases) although boron-carbon substitution in borocarbides is less pronounced than nitrogen-carbon substitution in metal carbonitrides. 

Steels are basically classified as carbon and alloy steels which are defined by national and international standards, e.g., ASTM and DIN. Carbon steels contain less than 1.65% manganese, 0.6% silicon, 0.6% copper, plus boron and deoxidizers as well as carbon as the principal additive increasing hardness. Manganese also... 

Built of stainless steel containing a neutron poison such as gadolinium or boron. 

Neutron Shield and Thermal Barrier The neutron shield consists of a cylindrical stainless steel container filled with boronated graphite material which is positioned beneath the gamma shield. The container is approximately 356 mm (14 in.) in length and is intended to restrict activation of components in the upper portion of the ONCA. 

An 8% Al-Cu alloy, oxidizing in air at 750 C in the presence of M0O3 vapor from an adjoining molylxlenum wire not in contact, was found to react at an abnormally high rate [31], Similar accelerated oxidation in air was reported for stainless steels containing a few percent molybdenum or vanadium [32], or as little as 0.04% boron [33], The oxidation products were voluminous and porous. 

P-BN tools work satisfactorily in hardened steel up to contact temperatures of 1000°C, since there is no chemical reaction between boron nitride and iron. This, however, also depends on the binding phase of the polycrystalline materials and can lead to adhesive wear [24, 25]. In hard steel, the main wear mechanism on the tool is abrasion by hard alloy carbide particles [26]. In the case of Co-based super alloy (Vitallium), the results on hard-BN tool wear are somewhat incongruous [27, 28], while Inconel 718 can be machined under proper selection of the cutting conditions [29]. Apparently, austenitic steels containing a high percentage of Co are difficult to cut by hard-BN tools, due to the formation of cobalt nitrides which leads to high tool wear [8]. 

Activation shapes, critical rod positions, and temperature coefficients were calculated for a slab experiment which was operated at various temperatures in the Bettis High Temperature Test Facility. Control was achieved with four Ag-in-Cd blade rods inserted axially in 1.5-in. water gaps. The slab contained boron septa which were 0.090-in. boron-stainless steel plates with a 2200 m/sec optical thickness of 1.0. 

L steel containing 1 wt% tmron 304-L steel containing 1.5 wt% boron Uranium depleted to 0.2 wt%... 

The reactor module components are contained within three steel pressure vessels the reactor vessel, a steam generator vessel, and connecting cross-vessel. The uninsulated steel reactor pressure vessel is approximately the same size as that of a large boiling water reactor (BWR) and contains the core, reflector, and associated supports. The annular reactor core and the surrounding graphite reflectors are supported on a steel core support plate at the lower end of the reactor vessel. Top-mounted penetrations house the control-rod drive mechanisms and the hoppers containing boron carbide pellets for reserve shutdown. 

Catastrophic branching chain reactions are prevented by inserting boron-containing steel or boron carbide rods which control the number of neutrons. 

Figure 9. Autoradiographs for two casts of stainless steel containing (a) 3 ppm boron and (b) 90 ppm boron, show ing enhanced boron segregation to grain boundaries in (b).

For a 5-mw experiment, control of 15% reactivity appears to be ample and can be obtained with four 2 % Cr-1% Mo steel rods of about 2-in. diameter. Blacker rods containing boron could, of course, be used to increase reactivity control. A study of various arrangements of identical rods in a ring around a central rod indicates that the optimum position of the ring occurs at about 1/4 of the distance from the reactor center to the (extrapolated) radius of the reactor core. 

---