Some images of the project:
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| Sliding plate welding |
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| Guide Pin welding |
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All of them just have only 2 purposes: The first is repair and then is protect the equipment in long-life service especially in the harsh environment such as Heavy Industries, Chemical environment, and Wherever wear appearance (Wear is defined as a progressive deterioration through loss of material and then leading to the bad performance of equipment.
Planning for wear in maintenance and repair operations is one of the keys to the success of business.. So, today the topic will demonstrate the importance of Hardfacing, used as a preventive or as a remedial measure.
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What is Hardfacing?
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- LM (Loesche)
- Ube (UM)
- MPS, MPV (Gebr. Pfeifer)
- RM (Polysius)
- CK (Kawasaki)
- Axtox, Fuller, OK (FLSmidth)
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“Published parameter” may not be well performance as we had expected.
[tintuc] To be honest, BCC was officially built in 2014 by a group of welding engineers from the Hanoi University of Science and Technology (HUST)
We are all in the same boat on the passionate ocean of engineering and manufacturing technology. Since its establishment in 03/2010, and was strengthened in 2014, BCC has already decided to become the Expert of Abrasion-Resistance Solutions, Repairs & Maintenance Services in the field of Heavy Industries. BCC gradually became the Manufacturer & Supplier:
We believe that our solutions are second to none in terms of durability, reliability, flexibility and cost-effectiveness in Vietnam.
For further vision, This name "BCC" is optimized from the Vietnamese name “Bao Chi”, with transformation in the psychology of business. It has been presented via the slogan:
- “More than a good Partner!”. It's the symbol of BCC's spirit, the core value that BCC is really willing to build. In particular, it means embracing a people-centered. Quality Human is the core of the business. And BCC has been using this slogan to gain 3 direct relationships that are absolutely believed in which in order to grain sustainable development!
This is the special relationship that everyone needs to build and strengthen. It was expressed in three dimensions: From short to high - From hollow to deep - From strange to friendly.
The link of “Buyer – Seller" is the first step of all no matter any organization, any company also has to start with. In this relationship, there are reflective benefits sometimes as the Buyers want to buy high-quality goods at budget prices but the Sellers was on the other hand. And that's why this relationship is very hard to get sustainable.
The Partnership: When the relationship is fostered to Partnership for development, sharing in the benefits and both strong belief in each other. And if it's maintained for the long term, we have a good partnership. Although, everything can happen beyond expectation, whenever if it does not bring for one or the other, the relationship will be shaken.
And "More than A Good Partner" is the goal that BCC gains toward. More than a good partner, we have the nature of friendship in which economic benefits do not put on the top. Understanding, empathy, mutual support and sharing are everything.
THE COLLEAGUE RELATIONSHIP
BCC luôn đặt con người là trung tâm để đặt và giải quyết vấn đề. Và Đội ngũ là máu thịt của BCC. Xây dựng đội ngũ là một trong nhưng nhiệm vụ sống còn. Nhưng câu hỏi đặt ra là tiêu chí là gì? Cơ sở nào để có được một đội ngũ vững mạnh, tin tưởng nhau, tâm huyết xây dựng.
Mối quan hệ “người cùng công ty“. Tổ chức được cấu thành từ các thành viên đến từ nhiều nơi, nhiều hoàn cảnh, trình độ và niềm tin khác nhau. Bởi Vậy thông thường, chúng ta bắt đầu bằng mối quan hệ của “người cùng công ty”, là cấp độ khởi thủy và cơ bản nhất. Ở cấp độ này, đôi khi mỗi người sẽ theo đuổi một tiêu chí và mục đích rất khách nhau. Điều này xuất hiện rất nhiều ở các doanh nghiệp và tổ chức hiện tại. Nó là yếu tố làm cho các tổ chức không thể đi một cách bên vững.
Một quan hệ “Cộng sự“. Khi những “người cùng công ty” nâng cấp mối quan hệ và coi nhau là cộng sự, là đối tác trong công việc. Họ bắt đầu có những điểm chung về lợi ích kinh tê. Ở mối quan hệ này, chúng ta có xu hướng làm tốt nhiệm vụ của chúng ta để đảm bảo sẽ có một kết quả chung tốt. Và khi mối quan hệ cộng sự được duy trì và phát triển lâu bên, chúng ta sẽ có mối quan hệ “đối tác tốt“.
BCC hướng đến việc xây dựng và nâng tầm mối quan hệ “đối tác tốt” trong nội bộ của BCC. Ở đố, những người đồng nghiệp, cộng sự tốt có thể coi nhau như anh em, như bằng hữu. Và luốn tìm mọi cách, cơ hội để tạo điều kiện hỗ trợ và giúp đỡ nhau cả trong công việc và ngoài cuộc sống. Và Khi đó BCC có một cái được gọi là “GIA ĐÌNH BCC“
Để đi dài, đi bên vững, BCC không thể chỉ dựa vào các thành viên sáng lập, những cổ đông ban đầu. Mà chắc chắn, BCC sẽ phải đón nhận thêm các nhà đầu tư, cổ đông mới. Và Xây dựng mối quan hệ giữa các cổng đông, thành viên sở hữu là một trong 3 mối quan hệ quan trọng mà BCC muốn xây dựng. Và đương nhiên, nó cũng sẽ phải trải qua 3 cấp độ tự cơ bản đến nâng cao.
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2.0 PROCESS AND BASE MATERIALS
2.1
2.2 Roller's Base Material
This one considers the restoration, hardfacing process of the casting roll in steel industry. The type of material used in this process is mentioned in EN 10269, 16CrMo44, 25CrMO4, 42CrMo4 or equivalent base. The composition of the steels is mentioned in Sheet 1
Sheet 1: Material's chemical composition3.0
In which, D430 welding wire is used for primer welding. Welding metal is specially used for rollers with a 42CrMo4(base material) or equivalent composition which has a carbon content of at least 0.3%. D414N is used for the next overlays. Depending on the desired, the number of layers can be 2 or more.
If it's 16CrMo44 and 25CrMo4 rollers, D430 can be used directly after the surface has been thoroughly cleaned before welding without the use of a primer.
D430 contains low carbon, low silicon, low chromium alloy, low molydenum, low another weld metal. and medium carbon D414 wire, martensitic steel weld metal with added Nickel, Molydenum and Vanadium. The weld metal also includes the certain amount of Nitrogen. This combination gives the weld overlay a medium-carbon heat treatment structure similar to that of martensitic steel. Therefore, it is designed for hard and tough materials. The addition of Nitrogen while welding will bring harder and more wear-resistant in applications working under high pressure and high temperature, Temperature cycle.
4.0 TECHNIQUES AND PARAMETERS
The advantage of SAW alloy welding wire is that the higher ratio welding overlay (width, height). The overlay also have no difference between the welding top and welding bottom.
An outline plot of the fillet surface is shown in Figure 1. In general, the height of the overlay (SAW) process will be lower than that of others welding process.
For the Weld Overlay, the overlapping of adjacent lines can significantly reduce the deformation of the welded structure (Figure 1). Therefore, locating the wire during welding will ensure a higher weld overlap (approximately 50%) to reduce the deformation of the structure shown in figure 2.
Figure 2 -Effect of weld overlap
5.0 HEAT TREAMENT AND METHODS OF REDUCE RESIDUAL STRESS
Welding is a fabrication process through the application of heat, which will cause residual stress(mainly the result of thermal expansion) after the welding work is completed. The purprose of "Heat Treatment" is to reduce residual stress and rearrange the structure of weld metal. With small rollers(Mill rolling) are possible to use heat treatment furnace to do this. For large size (Support Roller) must be heat treated and temperature controlled by a heat treatment machine(6 channel program controllers) after welding. The temperature control process is carried out as the following:
The hardness after welding, heat treatment is shown in figure 4. The hardness after heat treatment is 40-42 HRC. Temperature control is very important. As if the temperature exceeds the upper limit (>450 degrees), the microstructure of weld will be roughened and soften the weld metal.
Figure 4: Effect of heat treatment and surface hardness of welding overlay
6.0
Recommendation process for Build-up, Hardfacing of Support Roller:
6.1 Surface preparation.:
Rollers surface should be cleaned to free of any loose material, dirt, oil, grease, etc.…
Do inspect both on the surface and inside the structure by Ultrasonic Testing. In case there are cracks, it should be repaired with welding filler wire.
6.2
Roller has been existing residual stress and it surface has been partially hardened. And that's the reason Roller should be destressed by 400-450 degrees for approximately One hour per inch of thickness (1h/1inch) and being cooled slowly to reduce the pre-existing residual stress.
6.3
Heat to a minimum of 250 degrees before welding and keep in steady temperature (not to exceed 250 degrees) throughout the welding process.
6.4
Depending on the roller composition, welding procedure used with D430 as primer and D414 as filler weld.
With optimal welding parameters, each layer of welding will be 2-3mm thicker on diameter. Welding parameters as mentioned in Welding Procedure.
The temperature should be maintained at 250 degrees in the whole welding process.
The roller must be heat treated to reduce residual stress and rearrange the microstructure of weld metal..
6.6 Machining
After heat treatment, it will be machined to desired dimension. Surface parameters: Dimensions, surface roughness, concentricity must be strictly controlled to ensure the operating after, it directly affects the service life.
6.7
7.0 PROCESS NOTES
To achieve the expected results: Please! Follow the instruction and warning during process.
8.0
BCC is focusing on providing the repair, replacement and refurbished solutions using overlay welding technology and surfacing technologies. You can find the details of our products and services at below link
