Service HotlineScrew (pinyin: luógǎn, English: screw): a cylinder with a spiral groove cut on the outer surface or a cone cut with a tapered spiral groove. The screw has a different head, the head is called an external hexagon screw. There are others, such as large flat screws, socket head screws and so on.
The upper part of the T-bolt is a screw rod, and the bottom end is a T-shaped head. It is equipped with a sleeve with an anchoring plate. The fastening equipment is installed by the anchoring force between the T-shaped head and the anchoring plate. The appearance of the equipment after installation is shown in Figure 1, in which the figure composed of black lines is a component composed of T-bolts and integral sleeves. When constructing civil foundations, the sleeves should be pre-buried first, and the T-bolts will not be used until the equipment is installed. Anchor into the sleeve.
Guangdong Yueluo Hardware Industry Co., Ltd. discloses a rivetless rivet, which includes a nail body and a mandrel, wherein one end of the nail body is provided with a nail body brim, and the nail body brim is provided with a nail body. A coaxial counterbore, the nail body is provided with a through hole coaxial with the nail body, the counterbore is communicated with the through hole and its diameter is larger than the diameter of the through hole, and one end of the mandrel is provided with a mandrel cap The other end is provided with a clamp head, and the end is provided with an elastic groove for retracting the clamp head inward or opening it outward. The clamping head on the core is clamped on the boss formed by the countersunk hole and the through hole. The above-mentioned rivet-free rivet is not only simple, compact and reasonable in structure; riveting is simple and does not require professional tools and equipment; and it is easy to disassemble after riveting, can be reused, has a wide range of applications, and is reliable and stable in connection.
The quality of electroplating is measured primarily by its corrosion resistance, followed by appearance. Corrosion resistance is to imitate the working environment of the product, set it as the test condition, and perform a corrosion test on it. The quality of electroplating products shall be controlled from the following aspects: 1. Appearance: Partial uncoated, scorched, rough, gray, peeling, crusted, and obvious stripes are not allowed on the surface of the product, and pinholes, pitting, and black plating are not allowed. Slag, loose passivation film, cracks, peeling off and serious passivation marks. 2. Coating thickness: The operating life of fasteners in corrosive atmosphere is proportional to its coating thickness. The general recommended thickness of economical electroplating coating is 0.00015in ~ 0.0005in (4 ~ 12um). Hot-dip galvanizing: the standard average thickness is 54 um (43 um for diameter ≤ 3/8), and the minimum thickness is 43 um (37 um for diameter ≤ 3/8). 3. Coating distribution: With different deposition methods, the aggregation method of the coating on the surface of the fastener is also different. During electroplating, the coating metal is not uniformly deposited on the peripheral edge, and a thicker coating is obtained at the corners. In the threaded portion of the fastener, the thickest coating is located on the thread crest, gradually thinning along the flank of the thread, and the thinnest deposit is at the bottom of the thread, while hot dip galvanizing is just the opposite, the thicker coating is deposited on the inside corners and On the bottom of the thread, mechanical plating tends to deposit the same metal as hot-dip plating, but is smoother and has a much more uniform thickness over the entire surface [3]. 4. Hydrogen embrittlement: During the processing and processing of fasteners, especially in the pickling and alkali washing before plating and the subsequent electroplating process, the surface absorbs hydrogen atoms, and the deposited metal coating then traps hydrogen. When the fastener is tightened, the hydrogen is transferred towards the most stressed parts, causing the pressure to build up beyond the strength of the base metal and producing microscopic surface cracks. Hydrogen is particularly active and quickly seeps into the newly formed fissures. This pressure-rupture-penetration cycle continues until the fastener breaks. Usually occurs within a few hours after the first stress application. To eliminate the threat of hydrogen embrittlement, fasteners are heated and baked as soon as possible after plating to allow hydrogen to seep out of the plating, typically at 375-4000F (176-190C) for 3-24 hours. Since mechanical galvanizing is non-electrolyte, this virtually eliminates the threat of hydrogen embrittlement, which exists in galvanizing using electrochemical methods. In addition, due to engineering standards, it is forbidden to hot-dip galvanize fasteners with hardness higher than HRC35 (Imperial Gr8, metric 10.9 and above). Therefore, hydrogen embrittlement rarely occurs in hot-dip plated fasteners. 5. Adhesion: Cut or pry off with a solid tip and considerable pressure. If, in front of the blade tip, the coating peels off in flakes or skins, exposing the base metal, the adhesion shall be considered insufficient.
The process factors that affect the quality of high-strength fasteners include steel design, spheroidizing annealing, peeling and dephosphorization, drawing, cold heading, thread processing, heat treatment, etc., and sometimes the superposition of various factors.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: red copper rivets, metric hexagonal nuts, nylon flat head bolts, shaped anchor bolts and other products, we can provide you with suitable fasteners for you solution.
