Problem

A global leader in valve manufacturing and automation control product distributor in the US and Venezuela was facing acute corrosion, erosion and wear rates of eccentric e-plug valves used in iron ore mining plant in Latin America

The eccentric plug valve disk encountered frequent failures and rapid wear rates in pneumatic conveying of iron ore. 4 inch to 16 inch size butterfly valves were used. The OEM valve butterfly disks were manufactured in carbon steel casting ASTM A 216 WCB grade and then hard-faced chromium plated 50 microns.

The disks lasted only 27 hours of service during shut-on and shut-off operations with a total service life of 3 months.

Evaluation, Assessment, Recommendation And Solution(s)

ACME reverse engineered a 4-inch valve disk, manufactured the replacement part in high chromium high alloy white iron-ACME Taurus 30.

The high chromium high alloy white iron was further micro-alloyed with molybdenum, titanium, vanadium.

The valve component was cast, cleaned and CNC machined using PBCN inserts owing to its high hardness HRC 50+, that offers high wear and abrasion resistance. The bore of the valve disk was CNC EDM speciality machined and supplied to the customer

Result

The supplied part outperformed OEM. Useful life was more than 3 years. Less plant down, Lower maintenance cost and high uptime of the dense phase pneumatic conveying line of iron ore.

The customer satisfied with the solution and performance immediately issued next order for high wear and abrasion resistant valve seat rings and plugs in Stellite 6 (Cobalt base alloys) to use in highly corrosive bauxite slurry. The supplied eccentric plug supplied was cast in SS316 and then hardfaced with Stellite 6, outperformed OEM product and was 40% lower in cost.

Problem

India’s leading state government owned pulp and paper manufacturing plant located in southern India with an integrated power plant, sugar plant and its own forestation. Pulping mill is bagasse and eucalyptus tree raw meal based. The pulping mill and paper plant OEMs were Bauer Refiner and Andritz AG Pressafiners.

1. Pulping mill Breaker Bars suffered severe wear-corrosion
2. Pressafiner Screen Bars suffered wear-corrosion
3. The OEMs were charging high for replacement parts with long delivery period to supply the spares as long as 12 months
4. Materials for breaker bars and screen cage pressafiners were Cobalt Alloy 6 and lower cost solution 17-7 PH precipitation hardening stainless steel

Evaluation, Assessment, Recommendation And Solution(s)

ACME team visited the plant and made detailed evaluation of wear, corrosion and failures of the breaker bars and pressafiners.

ACMECAST successfully developed, manufactured and supplied Bauer Double Disc Refiner Spares when OEM declined to provide spares for its equipment siting old discontinued model as the reason and continuously suggested the Pulp and Paper Plant to replace with new Bauer Double Disk Refiners.

ACMECAST successfully reverse engineered breaker bars- main cage and manufactured them in Modified ASTM A 743 Grade CA-40 and CC-50 alloys, solution annealed and tempered martensite and bainite final microstructures.

ACMECAST also developed and supplied pressafiner screen bars based on old samples in ASTM A 743 CA-40 Modified alloy.

Result

Breaker bars main cage performed well and offered lower life cycle cost solution with 40% cost savings, faster delivery and import substitute solution to the plant.

The pressafiner screen bars were successfully developed after three iterations as those developed by us were from precision sand casting (ceramic coated) route rather than lost-wax investment casting process. The pressafiners were machined, and precision grinded to eventually achieve and maintain the same tolerances that had been obtained by precision grinding investment cast pressafiners bars. The performance of ACME Modified ASTM A 743 CA 40 alloy was better than 17-7PH alloy of OEM. Cobalt Alloy 6 as component metallurgy was not selected due to its high cost.

Many other import substitute replacement parts were developed and supplied to the pulp and paper plant, including Air-Injection Nozzles for CFBC Boilers at its power plant along with blow pipe assemblies. ACMECAST was recognized as most innovative vendor by the plant management and operational team towards saving foreign exchange currency and indigenously developing parts in high performance alloys. To our surprise we were approached by the OEM to supply the spares to them rather than their customer plants.

Problem

India’s leading fully integrated steel plant in western region faced high temperature wear, abrasion, erosion and corrosion issues at its Sinter Plant (Cold and Hot Sinter Areas), Sponge Iron Plant, Blast Furnace.

1. Sinter plant- Sinter Breaker Hammers were experience rapid wear rates. Reversible Impact Crusher Hammers were supplied by an exiting vendor in low alloy steel with hardfacing of 2-3 mm done on the hammer head impacting area
2. Sponge Iron Plant- Has OEM Midrex DRI. The Lower Burden Feed (LBF) and Middle Feed Burden (MBF) Breaker Discs were suffering from rapid wear, abrasion and demanding frequent shut down (every 3 months) and replacement of breaker discs in 8-12 months of operation
3. Sinter Plant-Sinter Roll Crusher- Sinter Horn Teeth handling hot sinter at 800°C were experience high temperature corrosion, wear and abrasion including metal
   dusting and heavy metal loss as scaling
4. Blast Furnace- OEM Paul Wurth, Burden Roll Over Feeder Plate was experiencing high wear and abrasion rates due to falling burden feed and high service temperature, that required repair shut down in 6-8 months, with impacting feed making holes in the wear plate which were plugged with hardfacing material and repair plates.

Evaluation,Assessment, Recommendation And Solution(s)

ACME team visited the plant and made detailed evaluation of wear, corrosion and failures of at Sinter Plant, Blast Furnace, Sponge Iron Plant, Continuous Casting Plant and Plate Mill

1. Sinter Breaker Hammers for limestone and dolomite crushing ACME suggested manufacturing and supplying inter breaker hammers in ACME Modified Austenitic Manganese Steel (AMS) ASTM A 128 Grade E1 and E1, titanium killed in solution annealed condition. Supplied Hardness HRC 45-55 which improved in work hardened end condition to HRC 60+
2. Sponge Iron Plant- MIDREX Spares-Breaker Discs ACME manufactured and supplied Breaker Discs in ACME Modified ASTM A 297 HD Alloy in both toothed and plain breaker discs, reverse engineered from drawings and samples.
3. Sinter Plant- Sinter Roll Crusher Horn Teeth A detailed 50-page evaluation and case study report with recommendations were submitted to the management and plant operation team for solution to handle high temperature erosion and wear of sinter horn teeth- 52 nos. mounted on the sinter roll crusher shaft
4. Blast Furnace- Wear Plates for the Burden Roll Over Chute ACME Manufactured and supplied composite wear plates 4 no. to match the dimensions of the OEM Blast Furnace wear plate replacement part. The composite plates consisted of 12mm base plate of IS 2062: Grade B with 8 mm High Chrome Hardfacing (applied in two passes) using submerged arc welding technique

Result

1. ACME developed AMS ASTM A 128 Modified E1 and E2 reversible impact hammers outperformed the existing product being used at the Sinter Plant. Useful life of the hammers doubled before asking replacement. No hardfacing was required. More than 70% of hammer head was used in reversible impacting service conditions. Previously used hammer achieved 2500-3200 Metric Tonne of closed circuit crushing of limestone and dolomite while ACME products achieved much higher crushing tonnage. Grade E1 (1% Molybdenum) titanium killed one set of 52 hammers resulted in 8000-12000 Metric Tonne of crushing, while Grade E2 (2% Molybdenum) titanium killed hammer set achieved 17800 Metric Tonne of crushing. The sinter plant team won the innovative solution award from Ernst & Young auditors in that year.
2. Supplied Breaker Discs replaced import substitute OEM product. The useful life of Breaker Discs was 5 years. 5 times more than the existing product. ACMECAST lately supplied another set of LBF Midrex DRI spare set to the plant after 5 years as repeat ordered supply.
   ACMECAST has submitted offer for Hot Sinter Breaker Discs for MBF at companies another Steel Plant (India’s Largest Private Sector Steel Plant) at Vijayanagar Bellary in heat resistant alloy OEM specified ASTM A 297 Grade HP alloy for handling high temperature sinter at 700-850°C.
3. Sinter Plant Roll Crusher Horn teeth were not ocured owing to company takeover acquisition that year. Following which the company was acquired by Indian company and did not go through the high capital purchase cost owing to budgeting constrain and resorted to using old solution. However, ACMECAST was approached by the same problem faced by USS Steel Corporation, now Arcelor Mittal Company at One of the Worlds Largest Plate Mill in the USA. The case study report for the same equipment used at its plant was submitted and approved by its Global R&D Centre for trail in the US plant for the recommended solution.
4. The supplied Blast Furnace Burden Roll Over wear plates outperformed OEM. They lasted more than 16 months without asking any maintenance repair. In shut down taken by the maintenance team, some in-situ weld repairs were performed which further extended the life of wear plates by 8 months. Overall useful life of supplied high temperature wear-abrasion resistant composite wear plate were 2.8 times more than previous product used at the plant.
5. Based on above performance of supplied steel plant spares, ACMECAST became a preferred Vendor at its three major integrated steel plants in India.

Problem

A global leader in manufacturing and supplying vacuum furnace was facing problem of cracking of studs during heat treating process. The company is based Poland.

Evaluation, Assessment, Recommendation And Solution(s)

Evaluation, assessment, alloy selection and manufacturing of charge support studs for Single Combined Thermal Process Heating Treating Furnace

Ammonia Nitriding + Nitro-carburizing + Steam-Water Passivation above 600°C service temperature

A detailed case study report of 15 pages were submitted to the customer examining the causes of rapid failures of furnace part, support studs made in corrosion resistant stainless steel grade AISI 316 in its carbo-nitriding furnace.

Titanium stabilized alloys solution was suggested and asked for trial implementation to overcoming cracking of stub supports

Result

The customer overcome the problem and also converted its furnace’s heat-treating shell in the same metallurgy as suggested of support studs. The customer, never encountered metallurgical failures in all the new supplies and replaced its previous furnaces supplied with old material spares, with new ones.

Problem

One of India’s largest fully integrated private sector steel plant on its western coast, has more than 150 cranes in steel plant service.

Cranes in the Steel Making Plant (Ladle Crane 350 T, with auxiliary crane 15T), and Plate Mill ranging from 20T- to 350T, crane wheels were suffering from shorter useful life, cracking, pitting and denting of track tread wheels cranes within 2-3 years of its service demanding repair, hard-facing or even replacement.

Evaluation, Assessment, Recommendation And Solution(s)

A plant visit was scheduled where on site crane wheel and axles were examined during operations at the steel making and plate mill at heights 30-40 m above the plant floor.

Both cast and forged crane wheel and axles were examined. Most of them were Chinese make, while some of the cranes were US, Europe makes as well.

A metallurgical failure analysis was performed on a set of carbon steel C45 gantry crane wheel following observation of excessive damage to the central tread surface, flange collar breakage, and cracking of wheel at track mating surfaces.

Rolling contact fatigue was considered as a possible failure mechanism due the presence of what appeared to be spalling. Metallurgical assessment and hardness testing of surface profiles revealed that portions (track width, collars and contacting ends), of wheel had not reached the specified hardness during heat treatment and non-uniform hardness was observed. It was determined that flame hardening was used which is not the correct heat treatment for the end application crane wheels, leaving the tread surface edges in a near normalized condition only.

Some wheels were cast while others were forged. Shafts were manufactured from forged C45 material mostly. Metallurgical defects were observed in wheels, non-uniform mechanical properties. The core of the wheel was not found in ductile condition, hence cracks from the radial diameter were found to be propagating to the centre of the wheel towards the shaft diameter and the hub region. Continual contact with the rail during the service allowed for plastic flow of the softer materials across the surface, resulting on observed damage and wheel-axle failures demanding frequent replacement. Refurbishing of the wheels, and hardfacing were added costs and increased downtime of the cranes when service was most required.

Result

Acmecast developed four modules of alloy metallurgy for different cranes according to its service, application and duty requirements. C45, C55, En19, En24 crane wheels and axle shafts were manufacturing for various crane with crane wheel diameter ranging from 250 mm to 850 mm.

Complete virgin forged bar stock and wheel blanks were normalized, tempered, proof-machined, precision machined, while shafts were grinded to close tolerances post heat treatment. Proprietary heat treatment to wheels was applied that hardened and tempered the track width, collar and outer periphery of crane wheel to HRC 55-62, while keeping the rest of the wheel ductile.

The products performance exceeded the OEM product for more than 6-8 years, without asking repair maintenance, or hard-facing of track widths. Subsequently, we have supplied various solutions for crane spares, shafts, spindles and other mechanical spares to other divisions of the steel plant.

Problem

Cement Plant located in Western India, Rajasthan part of Novoco Vistas (formerly Lafarge India) encountered severe erosion and abrasion of Vertical Roll Mill (VRM) roller and table liners.

ACMECAST was asked to visit the plant and make evaluation of rapid wear of Raw Mill VRM, as well as Primary Crusher mills.

Evaluation, Assessment, Recommendation And Solution(s)

On a two-day plant visit, and an impromptu shut down taken for ACMECAST’s evaluation and assessment, various areas including mines, raw meal, crusher mill, additive mixing plant, raw mill, Vertical Roll Mill and Rotary Kiln were reviewed.

A comprehensive report of 75 pages, including 14 recommendations were presented to the plant head and the board of company.

Some key findings include extremely highly corrosion and abrasive nature of additive mixes, which were aggravating the wear rates in conjunction with the limestone from mines having quartz content.

The VRM of Geber Pfeiffer roller and table liners wear patterns were studied for last 5 years, and recommendations were made to use correct wear-abrasion alloy for VRM roller and table liners, correct selection of hard-facing materials for VRM roller and table liners, with correct welding procedure, protocol and repair standard operation procedures.

Result

The mill was started after the maintenance program done according to the recommendations and shut downs which were earlier every month and long shut down every three months, were extended to 6 months of cement plant up time.

Most shut downs were due to failure of VRM and Kiln areas.

New materials and good hardfacing repair solutions suggested has helped the plant team.

A new assignment of Air Injection Nozzle failure assessment was given to us for the captive power plant while the cement plant team and company management was satisfied with our findings, recommendations and solutions for replacement parts.