CAST IRON INSERTS,GROOVING INSERT,TUNGSTEN CARBIDE INSERTS

A Preparation method of Nanometer Ta

Tantalum-tungsten (Ta-W) alloy is widely used due to its high density, high melting point, high ductility, modulus of elasticity, good processing properties, high temperature strength, high corrosion resistance, weldability and low brittle-to-ductile transition temperature (BDTT). It is used in aerospace, defense, military, chemical, and nuclear industries. With the development of 3D printing technology, Ta-W powder has also become one of the main 3D printing materials, mainly used for printing complex or miniature Ta-W alloys, which also puts higher requirements on the performance of the powder.

This paper describes a nanometer Ta-W powder prepared by nano-in-situ composite technology. The nanometer Ta-W composite powder has high sintering activity, is easy to achieve high densification of materials, reduces internal defects of materials, and significantly improves the mechanical processing properties of materials, and can meet higher requirements for material properties in 3D printing technology. The specific procedures of its production are:

Step 1: Sol-coprecipitation

1) Weight 406g of ammonium paratungstate (APT) into a container containing 30L of fluoroantimonic acid solution, and add 300ml of surfactant polyethylene glycol PEG-600 dropwise, and stir for 30 minutes to obtain a sol solution; the acid solution was measured by tantalum oxide at a concentration of 100 g/L, and an HF concentration of 1.2 mol/L.

2) Add concentrated ammonia water (concentration 9.6N) to the sol solution, add slowly while stirring; until the pH of the solution=9~10, stop adding concentrated ammonia water, and let the pH change after standing for 30 minutes to ensure the change.

3) The precipitate was filtered using a suction filtration apparatus, and the precipitate was sufficiently washed by using a drum ammonia hot water having a concentration of 0.3 mol/L at 75 ° C until the fluorine content in the precipitate is less than 0.5%. Then, the precipitated and filtered powder is placed in a hot air circulating oven and dried at 120 °C for 4 hours. After screening through 100 mesh sieve, a precursor tungsten carbide cutting tools composite powder composed of Ta(OH)5, (NH4)10(H2W12O42)•4H2O phase can be obtained.

Step 2: Hydrogen reduction

The composite powder obtained in the step 1 is heated in a fourteen-tube hydrogen reduction furnace to a temperature of 900 ° C for one hour to obtain a tantalum oxide-tungsten (chemical composition (Ta, O) and W) composite powder;

Step 3: Alkali metal reduction

1) Transfer the tantalum oxide-tungsten composite powder obtained in the step 2 to a reaction vessel (special equipment for stirring sodium reduction), and add alkali metal sodium, calcium chloride, potassium chloride and sodium chloride, and add 1700 g of sodium. 5020 g of calcium chloride, 5020 g of potassium chloride and 5020 g of sodium chloride. After the completion of the feeding, the reaction vessel is evacuated to a vacuum, the degree of vacuum is not more than 26.6 Pa, and then argon gas is introduced as a shielding. Raise the temperature to have a reduction at 920 ° C for 4 hours.

2) When the sodium reducing material is cooled, the material is peeled off from the reaction vessel and being broken into pieces. Then use a pure water to wash away the soluble salt and excess alkali metal, until the conductivity of the solution less than 50 μs/cm. Next, wash with a concentration of 40 % nitric acid for 2 hours, the pickling end point is the solution conductivity <30μs/cm, and then washed with 80 ° C pure water until the solution conductivity is less than 20μs / cm, the obtained powder is placed in a vacuum oven, drying temperature 80 ° C, drying time is After 8 hours, a nanometer Ta-10 wt%W composite powder is obtained.

The powder properties were tested, wherein the grain size was 10 to 200 nm, and the relevant element contents were: W: 9.6%, C: 0.02%, N: 0.065%, O: 2.8%, K: 0.002%, Na: 0.0035%, Ca: 0.002%, Fe: 0.01%, Ni: 0.0018% and the rest content is tantalum.

Step 4: Magnesium reduction deoxidation

Add 110 g of magnesium flakes to the Ta-W composite powder obtained in step 3, mixing them uniformly, putting them into the reaction vessel, first drawing into a vacuum, the vacuum degree is not more than 26.6 Pa, and then heating to 940 ° C by argon gas, and keeping the heat for 2 hours. After cooling to room temperature, the furnace is baked, and then washed with a concentration of 40% nitric acid for 2 hours. The acid pickling end point is a solution conductivity of <30 μs/cm, and then washed with 75 ° C hot pure water until the solution conductivity is <20 μs/cm, and dried for 100 times. The mesh was sieved to obtain an ultrafine (nano) yttrium-tungsten composite powder of Ta-10 wt% W.

The properties of the composite Ta-w alloy powder were examined, wherein the grain size is 10 to 220 nm, and the relevant element contents are: W: 9.5%, C: 0.01%, N: 0.035%, O: 0.28%, K: 0.001%, Na: 0.0015%. Ca: 0.001%, Fe: 0.005%, Ni: 0.0016%, and the rest is tantalum. The composite alloy powder has an average particle size of 2 μm. The powder yield of the entire process is 86%. The performance of Ta-W powder meets the requirement of 3D printing metal material.

Nano Tungsten Nitride Accelerated Preparation

Transition metal nitrides are interstitial compounds formed by nitrogen atoms inserted into metal lattices. They have high melting point, high hardness, high mechanical strength, excellent thermal stability and chemical stability. They can be used as cutting tools, wear resistant parts and high temperature resistant materials.

Nano tungsten nitride will have more remarkable advantages than tungsten carbide. Unfortunately, there is no mature production process. At present, the commonly Lathe Machine Cutting Tools used method is to synthesize tungsten nitride by temperature programmed reaction using WO₃ as raw material in N₂, H₂ mixture or NH₃. The disadvantages of the above methods are time consuming.

In order to improve the time-consuming disadvantage, some scholars proposed a preparation method of tungsten nitride nano powder. Tungsten nitride nano powder was synthesized by reaction in ammonia atmosphere with tungstic acid-based inorganic-organic hybrid layered compounds as precursors.

Weigh 5g H₂WO₄ and put it in a 1000ml conical bottle. Wet it with 2ml distilled water. Weigh 39G n-octylamine (0.3mol, 50ml) and 270g n-heptane (400ml). Mix them evenly. Add the mixture of n-octylamine and n-heptane into the conical bottle containing tungstic acid, stir vigorously at the side and start to be a yellow suspension. With the prolongation of time, the color of the suspension gradually fades and presents after half an hour. The white suspension was separated from solid and liquid by stirring for 24 hours and standing for 24 hours. The white suspension was washed by alcohol for 5 times (3000 r/min, 10 min) and dried at room temperature and vacuum for 30 hours. 10 g tungstate-based inorganic-organic hybrid layered compounds were obtained.

0.42g tungstic acid-based inorganic-organic hybrid layered compounds were weighed and put into the ceramic boat. The ceramic boat was put into a programmable low temperature tube electric furnace. The tube was quartz tube. The end of the quartz tube was sealed. Ar was passed through for 1 h at 100 ml/min speed. The heating began. Then the NH₃ flow rate was 120 ml/min, the heating rate was 20 ℃/min, the heating rate was 650 ℃, the holding time was 20 h, and 0.19g samples were obtained with the furnace cooling. The yield is 99%. The size of W₂N particles is about 40 nm and the surface area of BET is 8.2 m²/g.

Tungsten nitride was prepared in NH₃ by using tungstic acid-based inorganic-organic hybrid layered compounds as precursors. Tungstic acid-based inorganic-organic hybrid layered compounds were pyrolyzed in non-oxidizing atmosphere (such as Ar, NH₃). Highly active tungstic acid was obtained, which was easily nitrided with ammonia. Therefore, tungsten nitride nano-powder could be formed in a relatively short time, and tungstic acid-based inorganic-organic hybrid layers could be formed. The preparation process of these compounds is simple and can be prepared on a large scale.

Fly Fishing Rods Getting The Bendsl

Picking a fly fishing rod is a Wholesale SEA FISHING tricky endeavor. Do you go with your ego, expected fishing environment or something else? While length is a factor, the bend or action of the rod is a key factor.FlexibilityFly fishing rods are often defined by their flexibility. In laymen's terms, flexibility means how far the rods will bend when the same casting effort is used.Minimal BendA fly fishing rod that has minimum bend is often called a ?fast? rod. The lack of bend lets the angler get lots of speed on the cast. This speed allows you to cast very accurately and farther away than rods with more bends. While these benefits may sound great at first glance, a fast rod can be frustrating. There is no room for error when using the rod. If you are going to use one of these rods, you need excellent motion and timing. Generally, only anglers with a lot of experience should have TUNGSTEN WEIGHT a go at using fast rods.Moderate BendThe next step down from a fast rod is one with medium flexibility. These rods tend to have good flexibility, but the bend is restricted to the top half of the rod. The rod requires less perfection of motion and timing, but is fairly accurate. If you've been angling for a while and have the basic techniques down, a moderately flexible rod is worth a try.Slinky BendIf you are just taking up fly fishing, you should use a rod with maximum flexibility. While others suggest a moderate bend is better for beginners, a 'slinky bend? rod gives you a lot of leeway when it comes to learning to cast.Fly fishing is relaxing and enjoyable. Pick the wrong rod, however, and it can quickly become frustrating and stressful. If you use your brain, not your ego, when picking a rod, you will have a blast.

The Squeeze Cast Small Stream Fly Fishing

When heading out for an evenings go at a local small water Trout stream, you might consider the following tips.I suggest you use a Double Taper fly line versus a Weight Forward line. This fills up the spool a little quicker with less weight and is better suited for the many Roll Casts an evenings fly fishing on small streams usually requires. Also, use either an 8# or 12# backing line if you can find it. Not a real big deal but keeping the weight down on small stream outfits is useful.Small stream fly rods do not normally require a very long casting stroke. A key to accurate casting with these short rods (5' to 7') is to execute both your back cast and forecast with a very short casting stroke, the shorter the better. Smooth acceleration to an immediate stop, almost like punching a wall, then hold the rod stopped until the cast is almost completely laid out....then drop your elbow (without extending your arm or body) to present the fly.Another tip.........to increase speed and accuracy very quickly.....AS YOU ARE EXECUTING YOUR BACK CAST......OPEN YOUR 3 LOWER FINGERS......control the rod with your thumb and fore finger. (keep the back of the rod handle up against the fleshy part of your hand) HOLD THE ROD WITH THESE TWO FINGERS tungsten worm weights THRU THE BACK CAST. .........Just as you are finishing your fore cast......SHARPLY SQUEEZE.....THE 3 FINGERS TOGETHER AGAINST THE LOWER PART OF THE ROD HANDLE and your thumb against the top of the rod handle...... THIS GIVES A FINAL, RAPID ACCELERATION TO THE STOPPING of the rod.....SPEEDING UP THE LINE AND IMPROVING ACCURACY....TAKES A LITTLE PRACTICE BUT REALLY IMPROVES A CAST IN A TIGHT SITUATION.Give it a try and let me know how it works for you...I call this "The Squeeze Cast"....tricky name I thought......Best Joe @ Castitagain.

Molybdenum Powder Price - Jan. 29, 2018

This week, tight supply of molybdenum raw materials may continue in China and outside China, and manufacturers will maintain good mentality. Though downstream enterprises have no plan for purchasing raw material, production companies would not reduce product prices.

Molybdenum raw material price in China is expected to stabilize. Steel biddings’ quantity failed to meet the market expectation and international price recovered last week, so traders who have strong willingness in trading may cut profits to sell and producing companies’ quotation would keep firm. Under the high tungsten carbide bars pressure of production cost, ferro molybdenum price is hard to rise and fall sharply. On the whole, customers’ stocking up before the Chinese Spring Festival is coming to an end, so the market tends to be stable. tungsten carbide plates Molybdenum price is expected to stabilize this week.

Prices of molybdenum products on Jan. 29, 2018

Picture of molybdenum powder

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