Introduction
The manufacture is the process of making wares by machinery when carried on systematically with division of labor. In this project of 4Cr14Ni14W2Mo, S32590 the manufacture is similar to cast steel, mainly including the casting, annealing and finish machining.
1.Casting
The casting is transferring molten steel to a mold to cast the component whose forming method mostly thermoforming, [1] which heating a thermoplastic material and shaping in a mold. As the tooling has
Been selected, the metal is heated to a pliable temperature and shaped into the mold within vacuum pressure, air pressure or both. Then the material is cooled to solidify and removed from the mold, keeping it mold shape. [1]
Thermoforming has advantages in lower tooling cost than injection molding or blow molding, fast prototype speed and easy to control component shape. [2]
2.Solution annealing
Solution annealing is a high temperature heat treat process bringing the alloying elements of the material into a solid solution, in order to make the metal more workable and easier to shape.
This process heat the metal to 820-850℃ in the furnace (fig 1), then fast cooling immediately. After that, the material molecular structure will rearrange and make the metal less hard. In addition, annealing temperature also effects the distribution of austenite and ferrous. [3]
Figure 1. A solution annealing furnace for austenitic stainless steel forgings and fittings. [4]
3.Finish machining
The process is mainly the post-treatment after metal casting including descaling, cutting and finishing.
- Anodic Electrocleaning: Steel as anode, use outer cathode and phosphoric acid to electrify steel. This deplating action removes metallic outer layer and prevents the deposition of non-adherent metallic films and particles. [5]
Figure 2. The process of Anodic Electrocleaning. [6]
- Mechanical cutting or plasma jet cutting to cut steel into final size and shape
- Cold working including squeezing, bending, shearing and drawing to control dimension, Improved strength properties and obtain better surface finish. [7]
References
[1] Practical Guidelines for the Fabrication of Duplex Stainless Steel. 4th ed. London: The International Molybdenum Association; 2014.
[2] Learn More About Thermoforming, [internet]. ingeniven.com. 2020 © All Rights Reserved | Created by Plumb. [cited 27 May 2020] Available from: https://ingeniven.com/what-is-custom-thermoforming-advantages-and-disadvantages/
[3] + General Administration of Quality Supervision, Inspection and Quarantine of the P.R.C；Standardization administration of the P.R,C. GB/T 1221-2007 Heat-resistance steel bar. 2007.
[4] Solution Annealing for Austenitic Stainless Steels, [internet]. metalspiping.com. Copy©2016 | HeBei Metals Industrial Limited [cited 27 May 2020]. Available from: http://www.metalspiping.com/solution-annealing-for-austenitic-stainless-steels.html
[5] NabilZaki. Electrocleaning. Metal Finishing. Volume 97, Issue 1, Supplement 1, January 1999, Pages 136-141
[6] Electrolytic Rust Removal, [internet]. schoepp.hylands.net. Last updated on 02/13/2007 [cited 27 May 2020]. Available from: http://schoepp.hylands.net/electrolyticrust.html
[7] Cold Working Processes, [internet]. totalmateria.com. 2020. Date Published: Feb-2010 [cited 27 May 2020]. Available from: https://www.totalmateria.com/page.aspx?ID=CheckArticle&site=kts&NM=266