№ 4 (66), 2018
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Influence of galvanic Zn-coating on mechanical properties and features of destruction of the high-strength screws of 10.9 and 12.9 strength classes
The effect of a zinc coating, making with galvanic deposition, on the mechanical properties under tension, on hardness, impact toughness and fractographic features of destruction of brittle fracture zones of high-strength screws of 10.9 and 12.9 strength classes is investigated. Tensile tests on an oblique washer of both types of screws before and after coating revealed compliance with the requirements of GOST R 52643-2006 for high-strength screws of 10.9 and 12.9 strength classes. The increase in the hardness of the screws after galvanizing them are marked. A significant change in the fractures of impact samples is shown: after Zn coating the proportion of intergrain destruction increases significantly in fragile fracture zones of impact samples. A noticeable difference was revealed in the degree of hydrogenation of the screws M12 of 10.9 and M14 of 12.9 strength classes.
Rationing of the calculated value of the twisting coefficient of high-strength bolt sets
When creating friction bolted joints, the most common issue is about the proper designation of the calculated value of the twisting coefficient for calculating the tightening torque. The ambiguity of approaches to solving this issue, according to the authors, is due to the lack of necessary explanations in the industry regulatory documentation. Regulatory documents on bolting in the industrial civil building and bridge construction, listed in the article, indicate the need for input control of the twisting coefficient, but do not explain how this control should be conducted, how to evaluate its results and determine the calculated value.
Corrosion protection of fasteners, made of ordinary and high strength steel, in the XХI century
The article is devoted to the consideration of issues on the formation of a hot zinc coating and thermal diffusion zinc coating in powder mixtures on fasteners. It examines the physical-chemical processes of diffusion galvanizing, the kinetics of the formation of zinc coating on steel products (bolts). The results of accelerated corrosion tests of fasteners in environments with varying degrees of aggressive effects are given. It is shown that, when evaluating the corrosion resistance and protective properties of zinc coatings, the type of coating caused by the method of its formation is important.
Research of the work of anchor screws on evulsion out of concrete and fiber-concrete
The main results of studies of the work of anchor screws (they are also concrete screws or self-tapping anchor screws) for pulling out of concrete and fiber-reinforced concrete are presented. HECO-MULTI-MONTI MMS-S screws were tested. For the fiber-concrete mix, steel anchor fiber FSV-A-0.30/30 was used. According to the results of the research work, an algorithm for the selection of a single anchor screw, which allows to perceive the required axial tensile load without exceeding permissible deformations, was compiled.
Cable ties
The cable ties from polymeric materials are considered. Types of materials and their properties are specified. The options of products for various operating conditions, made on the basis of Polyamide 66, are presented. Recommendations for storing cable ties in working condition are given here. The author describes the method of ties testing.
Broken chain of the fastener market
Contextual advertising for a fastener company
The author describes the types of contextual advertising: searching, media, thematic and others. The features when advancing with help of contextual advertising in the segment of fasteners are marked. The main options of analytical services of the leading search systems are indicated.
Term formation by the second and third methods
MTK opens its own testing laboratory
New fasteners and tools
On the errors when working with adhesive systems
Glue joints have long been able to compete with welded, bolted and other "traditional" mechanical joints both in strength and durability of connections. At the same time, there is often a lack of understanding of the features of working with adhesives, which leads to errors. Frequent errors when working with adhesives and adhesive tapes – the wrong choice of glue and poor surface preparation – are considered. It is noted that the choice of the adhesive system, the calculation of the parameters of the adhesive joint and the technology of surface preparation is a process that requires not only specific knowledge, but also a laboratory for testing adhesives on the surfaces used in a particular project.
Volgograd Plant of Tractor Parts and Normals. Pages of history
Volgograd Plant of Tractor Parts and Normals is one of the oldest enterprises of Tsaritsyn-Stalingrad-Volgograd. The history of the plant began in 1899, when “Tsaritsyn Bolt-Riveting Plant was founded by the French. Trading House of Gardien and Vallos”. A brief history of the plant, which ended in 2018, is presented.
Standardization news
Associations news
Methods of making threads on metal products
Calendar of the foreign exhibitions
Calendar of the Russian exhibitions
At Metal-Expo’2018 – fasteners of new productions
MITEX exhibition has become more
Exhibitions-partners of the magazine
This issue of the magazine is prepared and published with the support of LLC "TK Bolt.Ru" (Russia), LLC "Europartner" (Russia), LLC "Rusbolt" (Russia), LLC "Trade firm "SK" (Russia), LLC "Trade House KM" (Russia), LLC "MTK FR" (Russia), LLC "Industrial solutions" (Russia), SACMA Group (Italy), Ray Fu (Taiwan), Koelnmesse (Germany).