1.Inconel 718 board introduction

Inconel718 board is a kind of high temperature heat-resistant, wear-resistant and corrosion-resistant material. Generally, the material of nickel-based alloy can resist heat up to 1000 °C. The Inconel718 board has the following features:

(1). Easy processing

(2). High tensile strength, fatigue strength, creep strength and breaking strength at 700 °C

(3). High oxidation resistance at 1000 ° C

(4). Stable chemical properties at low temperatures

(5). Good welding performance

2.Application field of Inconel 718 board

Due to its high temperature strength at 700 ° C, excellent corrosion resistance and easy processing, it can be widely used in various demanding applications. Turbine, liquid fuel rocket

(1) Cryogenic engineering

(2) Acidic environment

(3) Nuclear engineering

3.Inconel 718 board chemical composition

3.1 close to the brand

The materials of Inconel 718 are different in different countries, but the grades are close to each other, and the international is also universal and recognized. Here are the similar brands for Inconel718 from different countries:

(1) GH4169, GH169 (China)

(2) NC19FeNb (France)

(3) NiCr19Fe19Nb5, Mo3 (Germany)

(4) NA 51 (UK)

(5) Inconel718UNS NO7718 (United States)

(6) NiCr19Nb5Mo3 (ISO)

3.2 Chemical composition

Chemical composition Ni Cr Fe C Mn Si Mo S
Inconel718 50-55 17-21 Bal ≤0.08 ≤0.35 ≤0.35 2.8-3.3 ≤0.01
Chemical composition Ti Co Al Cu Nb B P
Inconel718 0.65-1.15 ≤1.0 0.2-0.8 ≤0.3 4.75-5.50 0-0.006 ≤0.01

4.Heat treatment process

Inconel718 alloy is difficult to process in the field of machining.

(1). Preheating

The workpiece must be surface cleaned before and during heating to keep the surface clean. If the heated environment contains sulfur, phosphorus, lead or other low melting point metals, the Inconel 718 alloy will become brittle. Impurities are derived from painted paint, chalk, lubricating oil, water, fuel, and the like. The sulfur content of the fuel should be low, such as the impurity content of liquefied gas and natural gas should be less than 0.1%, the sulfur content of city gas should be lower than 0.25g/m3, and the sulfur content of petroleum gas should be less than 0.5%.

The heated electric furnace preferably has a relatively precise temperature control capability, and the furnace gas must be neutral or weakly alkaline, and the composition of the furnace gas should be prevented from fluctuating in oxidizing and reducing properties.

(2). Thermal processing

The suitable hot working temperature of Inconel718 alloy is 1120-900 °C. The cooling method can be water quenching or other rapid cooling method. After hot processing, it should be annealed in time to ensure the best performance. The material should be heated to the upper limit of the processing temperature during hot working. In order to ensure the plasticity during processing, the final processing temperature should not be lower than 960 °C when the deformation amount reaches 20%.

(3). Cold working

Cold working should be carried out after solution treatment. Inconel718 has a higher work hardening rate than austenitic stainless steel. Therefore, the processing equipment should be adjusted accordingly, and there should be an intermediate annealing process during cold working.

(4). Heat treatment

Different solution treatments and aging treatments will result in different material properties. Due to the low diffusion rate of the γ” phase, the Inconel 718 alloy achieves the best mechanical properties through prolonged aging treatment.

(5). Polishing

The oxide near the Inconel718 workpiece weld is more difficult to remove than the stainless steel. It needs to be sanded with a fine abrasive belt. Before pickling in a mixed acid of nitric acid and hydrofluoric acid, sandpaper should also be used to remove oxides or salt bath pre-preparation. deal with.

(6). Machining

The machining of Inconel718 is carried out after solution treatment. Considering the work hardenability of the material, unlike austenitic stainless steel, Inconel718 is suitable for low surface cutting speeds.

(7). Welding

The precipitation hardened Inconel 718 alloy is well suited for soldering and has no tendency to crack after soldering. Adhesive properties, ease of processing, and high strength are several advantages of this material.

Inconel718 is suitable for arc welding, plasma welding, etc. Before welding, the surface of the material should be clean, free of oil, no powder notes, etc., and the polished metal should be polished within 25mm around the weld.




Eternal Bliss Alloy Casting & Forging Co, Ltd.

Technical Dept.


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