Hardeners formulas

Carbon Equivalent (CE) is an approximate measure of weldability expressed in terms of the sum of carbon content and the alloy contents divided by applicable factors to relate equivalence in carbon in effectiveness in hardening—and thereby cracking. Commonly used formulas with commonly accepted but rather arbitrarily set maximums are ... 

Aurantin, molecular formula and structure, 5 91t Ausimont, 7 641 Austempering, 23 287 Austenite, 23 272, 273, 275 decomposition of, 76 197-198 grain size of, 23 276-277 in hardening of steels, 76 196-197 phase transformations in, 23 277 transformation rates of, 23 282—283 Austenite phase, in martensite... 

In essence two types of carbonitride are formed in a Ti,Nb-hardened micro-alloyed steel. At high temperatures a predominantly TiN-rich carbonitride is formed. However, on cooling to lower temperatures a predominantly NbC-iich carbonitride also precipitates. Both caibonitrides are based on the NaCl structure and form part of a continuum usually described by a formula such as (TixNb. xXCzNi.2). This can be expanded to include elements such as V and Ta, so the formula becomes (TazTiyNb Vi.,. z)(CzNi.z). The formation of two types of carbonitride can be consisted due to phase separation and Fig. 10.54 shows a projected miscibility... 

Arsenic. As, at wt 74.91 exists in three modifications all corresponding to the formula As4i mw 299.64. The most common form is the crystalline or a-form, known also as metallic arsenic. Its mp is 814° at 36 atm press, sublimation point 615, d 5 = 72 at RT (5.6-5.9 for commercial grade) and hardness 3.5 Mohs. Prepn props are given in Refs 1-6 toxicity, fire expln hazards of As dust are discussed in Ref 7. Arsenic is used in some alloys and for hardening lead shot... 

If you still prefer to use an acid stop bath instead of water the most widely used formulas call for acetic acid in a 1% to 2% working solution. The only other ingredient sometimes added is a pH indicator dye (Formulas Stop and Hardening Baths Indicator for Stop Baths). 

For tray processing of paper it is not necessary to use hardener unless you habitually experience scratches on the print emulsion from handling. If scratches do occur, hardener should be added to the fixer. Start by adding one-third of the manufacturer s recommended amount and increase in one-third increments until the problem is eliminated For example, if the directions call for 45.0 ml of hardener, start with 15.0 ml if the problem persists, add another 15.0ml. It will be necessary to neutralize or wash out the hardener prior to most toning processes (Formulas Miscellaneous De-hardener). 

If a fixer with hardener has been used re-fix in Plain Hypo (Formulas Fixers Plain Hypo) or use Dehardener (Formulas Miscellaneous Dehardener) before toning. 

Use this formula for film or paper to reduce fixing times. The hardener is optional. 

F-5 is the standard sodium-thiosulfate-based formula. Many commercially marketed fixers are essentially unaltered versions of this formula. Use this formula for film and paper when hardening is desired. 

FILM Film should be clear in 5 minutes and fully fixed in 10. Discard when the clearing time is close to 10 minutes.The hardener can be mixed separately as a stock solution (see the following formula). 

This solution should be used prior to toning prints that have been hardened during fixing. The formula will soften the emulsion so that the print will tone and spot more easily and washing will be more effective. 

Quantitative tests of hardness involve indenting a material with a ball, cone, or wedge of hardened steel or other metal under a pre-determined pressure for a specific amount of time. The size and depth of the cavity left in the material being tested is then measured and a formula applied. The resulting value is the hardness, which, like Moh s hardness, has no units of measure. 

Gutta peavha in its pure fium is white, and in crude form can be brown or black. It has the same chemical formula as rubber but a di rent physical state. It was not vulcanised as it was for too valuable a material and was prized for its elasticity and plasticity, and would have been ruined by vulcanisation. It was very easy to mould and could take intricate patterns, but to be made into jewellery, it would have needed to be hardened in some way. Gutta percha was less durable than vulcanite, and cracked and deteriorated when closed to air over a lot period of time. Instead it kept... 

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