Bucket Teeth Research Articles

Introduction of evaluation procedure of excavator bucket teeth into maintenance and repair: Prompts

Introduction of evaluation procedure of excavator bucket teeth into maintenance and repair: Prompts

THE EFFECT OF HARD FACING PROCESS ON THE HARDNESS AND MICROSTRUCTURE OF BUCKET TOOTH FOR DIFFERENT MANGANESE CONTENT

High hardness and wear resistance of bucket tooth are required in the face of abrasion and impact. High manganese steel is hard and ductile, making it more suitable for bucket tooth materials. Bucket tooth can wear out and need to be returned to their original size, so that bucket tooth that have been eroded must be coated with a hard material, using a hard facing process. In this study, the hard facing process was carried out in bucket tooth containing 10.4%, 11.60%, 12.70%, 13.60%, and 14.60% men (manganese) elements, using hard facing electrodes of the AWS A5.13 (JIS Z 3251). Hard facing process was using SMAW welding with an average heat input of 1087.43 J/mm. The hard facing process shown that the hardness of weld metal was always lower than of HAZ (Heat Affected Zone) and base metal. The hardness of the weld metal was almost the same for all types of the bucket tooth, which was about 233.478 HVN.

Failure analysis and control of natural gas pipelines under excavation impact based on machine learning scheme

Third-party excavation operations pose a serious threat to the safe operation of natural gas pipelines, and quantifying the failure conditions of pipelines can effectively identify the hazards of excavation operations. Considering the current lack of test data on the full-size critical conditions of pipelines under different failure modes, to make the research results have better field application, this study aims to develop a failure prediction model, which is adopted for predicting the failure modes of the pipeline under different excavation conditions in order to propose control strategies. In this work, finite element analysis is combined with machine learning algorithms. The finite element analysis process derives the critical loads for different failure modes of the pipe and establishes the failure condition data set. Correlation analysis and sensitivity analysis were employed to investigate the influence pattern of the features. The prediction performance of different machine learning combination algorithms was tested, and a hybrid data-driven prediction model was established and combined with the excavation equipment parameters to determine the risk level of the excavation equipment and the risk area of the operation. The results demonstrate that the critical load value for failure grows when the strength of the pipe increases. The four features of yield strength, strength limit, pipe diameter, and wall thickness exhibit the highest importance scores. The bucket tooth wedge angle only influences the magnitude of the puncture critical load, with correlation and sensitivity coefficients being 0.315 and 0.116, respectively. In the test of the combined algorithm, the RFECV-CSVR-NSGAIII algorithm built in this study has the highest generalization performance, the mean absolute error percentage (MAPE) is lower than 0.0476, the coefficient of determination R2 reaches over 0.9960, and the prediction model has excellent accuracy. The prediction model was subjected to case studies to obtain rapid identification of risk levels and operational risk areas of excavation equipment.

A real-time and accurate detection approach for bucket teeth falling off based on improved YOLOX

Abstract. An electric shovel is a bucket-equipped mining excavator widely used in open-pit mining today. The prolonged direct impact between the bucket teeth and the ore during the mining process will cause the teeth to loosen prematurely or even break, resulting in unplanned downtime and productivity losses. To solve this problem, we propose a real-time and accurate detection algorithm of bucket teeth falling off based on improved YOLOX. Firstly, to solve the problem of poor detection effect caused by uneven illumination, the dilated convolution attention mechanism is added to enhance the feature expression ability of the target in complex backgrounds so as to improve the detection accuracy of the target. Secondly, considering the high computing cost and large delay of the embedded device, the deep separable convolution is used to replace the traditional convolution in the feature pyramid network, and the model compression strategy is used to prune the redundant channels in the network, reduce the model volume, and improve the detection speed. The performance test is carried out on the self-constructed dataset of WK-10 electric shovel. The experimental results show that, compared with the YOLOX model, the mean average precision of the algorithm in this paper reaches 95.26 %, only 0.33 % lower, while the detection speed is 50.8 fps, 11.9 fps higher, and the model volume is 28.42 MB, which is reduced to 29.46 % of the original. Compared with many other existing methods, the target detection algorithm proposed in this paper has the advantages of higher precision, smaller model volume, and faster speed. It can meet the requirements of real-time and accurate detection of the bucket teeth falling off.

Method of State and Residual Resource Assessment of Excavator Bucket Tooth Caps

Method of State and Residual Resource Assessment of Excavator Bucket Tooth Caps

Optimization of the CAT 318B L excavator teeth bucket structure topology design using the finite element method

Infrastructure development in this era has developed rapidly. Excavators are generally used to dredge rivers, dismantle roads, or demolish buildings. One of the most important components in an excavator is the bucket teeth. Bucket teeth generally have two important characteristics, namely maximum performance and wear life. Therefore, the author is interested in discussing one of the problems that exist in the bucket teeth excavator and optimizing the design of the bucket teeth that are already on the market in order to produce a lighter design. In this study, optimization of the bucket teeth excavator CAT 318 BL was carried out. In this simulation used linear static method for topology optimization process. The results obtained after topological optimization were found that the mass reduction in the first variable design was 0.22 kg and in the second variable design was 0.32 kg. In addition, the maximum von misses stress in variation 1 is 141,743 MPa, while in variation 2 is 145,879 MPa. The safety factor value of the first design variable is 2.92 and the second design variable is 2.84 where it can be said that the value of the stress that occurs in both designs, although tends to increase, is still declared safe.

Increasing in service durability of excavator bucket teeth by alloying in casting mould

Effective technology for producing of bucket teeth for increased operational durability excavators is described. Surface alloying of working elements in casting mould by wear-resistant PG-S27 powder and hardening of fastening holes by painting with fi ne chips of high-manganese steel are used. Production tests have shown the advantages of excavator bucket teeth cast using the proposed technology in comparison with steel 110G13L excavator bucket teeth using traditional technology. The prime cost of 1 ton of castings made according to the developed technology turned out to be significantly lower than prime cost of 1 ton of casting produced according to the traditional technology.

Influence of rock type on regularities of excavator bucket tooth crown wear

Influence of rock type on regularities of excavator bucket tooth crown wear

Design and analysis of biomimetics based excavator bucket and tooth

Within the scope of this paper, various bucket tooth designs and a biomimetic bucket design were created in order to produce a solution on digging efficiency which is one of the general problems of construction machines. These designs were inspired by giant anteater and American badger front claws. The inspiration aspect was diversified by integrating the paw and claw curves of the giant anteater and by bringing American badger claws into the design in different ways. Furhermore, the designed biomimetic bucket alternatives were compared between each other and the standard bucket equipment used in the market by making a computer aided static analysis. The compared criteria were the equivalent stress and total deformation formed on the bucket itself, the excavation equipment and the excavated soil. According to the analysis results, when the bucket tooth named P2 is mounted to the standard bucket, it has 42% lower Von-Mises stress on than standard bucket tooth. Additionally, it is exposed 4,7% less total deformation than standard tooth. Also, in terms of maximum Von-Mises stress formed on the soil model, P2 causes 17,5% greater stress than the standard bucket tooth.

Optimization of bucket tooth excavator design using topology optimization and finite element method

Purpose: This research discusses the optimization design of bucket tooth on the market to produce a lighter design but still maintains its strength, the type of bucket tooth is Verona PC200. Methodology: The optimization process in a bucket tooth applies the concept of topology optimization. A static linear analysis is performed using the finite element method to see the maximum stress that occurs in the bucket tooth. Then the method is determining the design variable of bucket tooth with applied a manufacturing constraint. Optimization gives the new design. Result: The maximum VonMises value is 403.81 MPa. After that topology optimization is done by selecting several variations of the design area which results in a reduction in mass in first variation of 0.72 kg and the second variation 1.49 kg. The mass reduction causes a change in stress that occurs in the bucket tooth to 451.8 MPa in first variation and 458.6 MPa in variation 2, but the stress is still in a safe condition. Value: Optimization of bucket tooth design in this paper can reduce the cost of production for bucket tooth with considering to keep the strength of bucket tooth.

PROCEDURE FOR DETERMINING THE MAIN GEOMETRIC INDICATORS OF THE PIPELINE BY THE MULTI-CRITERIAL OPTIMIZATION METHOD

Background The wall thickness of the main pipeline is mainly determined by calculating the internal pressure. The need to clarify the existing calculation methodology is associated with the presence of some natural and anthropogenic hazards of mechanical damage to the pipeline due to various types of mechanical influences. The existing methods for determining pipe wall thickness in Russian and American regulations determine the dependence of hoop stresses on internal pressure using the Barlow formula. It is assumed that the distribution of hoop stresses over the pipe wall thickness is uniform, and radial stresses are not taken into account. Meanwhile, in relation to areas of increased danger in the presence of external mechanical influences (earthquakes, landslides, mudflows and other destructive phenomena), the design of pipeline lines requires optimal consideration of these effects. Aims and Objectives The aim of the work is to study the issue of developing a methodology for determining the main geometric parameters of the pipeline using the method of multicriteria optimization. Results A method of shock-mechanical action for calculating the optimal thickness of the pipeline wall has been developed. It is assumed that the impact is exerted by the bucket teeth of an earth-moving excavator. The proposed optimization criterion is a scalar convolution of two particular criteria, the first of which determines the resistance of the pipe to puncture, and the second, the resistance to the propagation of the emerging crack. It is shown that the optimal value of the pipe wall thickness is directly proportional to the pipe diameter and hoop stress and inversely proportional to the minimum value of the yield stress, the length and width of the tooth acting on the pipeline.

Bucket Teeth Detection Based on Faster Region Convolutional Neural Network

The electric shovel is a bucket-equipped mining excavator widely used in open-pit mining today. The prolonged direct impact of the bucket teeth with hard and abrasive materials such as ore during the process of the mining excavation can cause the bucket teeth to break and fall off prematurely, resulting in unplanned downtime and productivity losses. In response to this problem, we have developed a vision-based bucket teeth fault detection algorithm with deep learning. Using a dataset based on the images of both real shovel teeth and 3D-printed models, we trained a Faster Region Convolutional Neural Network (Faster R-CNN) to obtain the number of normal bucket teeth and the positions of the bucket teeth from the images, using the additional bucket dataset from 3D-printed models to pre-train the network for improving its detection accuracy on the real bucket data. We compared the resulting Faster R-CNN model with the ZFNet, the ResNet-50, and the VGG16 and found our Faster R-CNN model to perform best in terms of accuracy and speed.

Study on Mechanical Properties and Microstructure of the Ultrastrong Low Alloy Wear‐Resistant Steel

Herein, a kind of the ultrastrong low alloy wear‐resistant steel suitable for excavator bucket teeth is prepared. The ultrastrong steel with good toughness and wear resistance is successfully prepared by the forging, quenching, and tempering processes. The yield strength, tensile strength, elongation, and hardness of the ultrastrong steel reached up to 1700, 1960 MPa, 7%, and 563HV, respectively. Optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM) are used to observe the microstructures of the ultrastrong steel. After the forging, quenching, and tempering, two types of martensite laths are formed in the matrix of the ultrastrong steel, i.e., the coarse laths with low‐density dislocations and the thin laths with high‐density dislocations and some ε‐carbides. Low‐temperature tempering allows the carbides to precipitate in large quantities, and maintains the matrix with high density dislocations in the thin laths, which is the micromechanism of the steel with high strength and high toughness, and good wear resistance.

The Effect of Finely Divided Martensite of Austenitic High Manganese Steel on the Wear Resistance of the Excavator Buckets Teeth

An analytical review of the effect of high-temperature thermomechanical treatment on the structure and properties of steels as a possible effective method of strengthening the teeth of excavator buckets. It is shown that the application of this method can have a positive effect not only on the hardness, but also on the entire complex of their mechanical characteristics, such as plasticity, impact toughness and fatigue resistance. In relation to Hadfield steel as the most frequently used material of the bucket teeth, it is noted that with increasing deformation grade of billets from 1 to 5, tensile strength of steel increases from 570 to 1030 MPa, yield strength – from 480 to 790 MPa, relative elongation – from 14.3 to 17.9 %, relative contraction – from 17.2 to 20.1 %, impact strength KCU – from 1.51 to 2.14 MJ/m2. This article presents the results of metallographic analysis and comparative tests for abrasive wear of Hadfield steel samples after typical heat treatment practiced at bucket teeth manufacturers and thermomechanical treatment. It is established that high-temperature plastic deformation of steel samples before quenching increases their wear resistance by 1.7 times. The authors attribute the detected increase in wear resistance to the formation of fine martensite in the surface layers of steel with a needle size of 3-10 nm, which increases its hardness by 47%. It is concluded that the presence of fine martensite in the structure of Hadfield steel can increase the service life of excavator bucket teeth made of this material. The results of this study are planned to be used in the development of an improved technological process for manufacturing bucket teeth of excavators.

Optimization of Bucket Tooth Excavator Design using Topology Optimization and Finite Element Method

Optimization of Bucket Tooth Excavator Design using Topology Optimization and Finite Element Method

Influence of Rake Angle, Bucket Width and Teeth Depth of Dragline Bucket on the Resistive Force in Different Rock Types

Draglines are used to dispose the overburden for exposing minerals in a surface mine. Draglines may be greater than 4000 t in overall weight, with bucket capacity ranging from 24 to 120 m 3 . The buckets are dragged against the blasted muck to fill the blasted overburden materials 1 . Bucket teeth fail easily while the excavator is being operated due to the fact that they are in direct touch with the rocks. The bucket teeth have an appropriate geometrical design for longer life and cost reduction 2 .

Improvement of mechanical properties by means of titanium alloying to steel teeth used in the excavator

The effect of Ti addition (0.15 and 0.20 wt%) on mechanical properties and wear resistance of steel excavator bucket teeth was investigated. Teeth were produced by commercial sand casting technique. After production normalizing, hardening, and tempering heat treatment procedures were applied to the teeth. Lath martensitic microstructure was observed and small amount of carbide particles were present in the microstructures of Ti containing ones. In addition, small amount of hard and brittle TiN particles were observed in the microstructure of 0.20 wt% Ti containing teeth. The best mechanical properties were obtained for 0.15 wt% Ti containing teeth with considerably high abrasive wear resistance. However, 0.20 wt% Ti containing teeth exhibited worst abrasive wear resistance and limited ductility due to the formation of TiN particles.

The interaction of the main actuators of hydraulic excavators

The operation modes of the main actuators of hydraulic excavators during their joint operation in the process of rock excavation are considered. It is shown that the main mechanisms for turning the boom of the handle and the bucket are part of hydromechanical units consisting of an engine (hydraulic cylinder) and a main mechanism in which the engine (the cylinder and the rod itself) and elements of the working equipment (boom, handle or bucket) are the links of the mechanism. It has been established that the relationship between the parameters of the mechanical energy of the engines and the power parameters implemented on the driven (output) links of the mechanisms depend on the magnitude of the extension of the hydraulic cylinder rod. Mathematical models of the main mechanisms are developed. A computational experiment was carried out to determine the actual values of energy-power parameters implemented on the cutting edge of the bucket (teeth) during excavation of rocks at characteristic points of the excavator's working area, as well as reactive loads in the rota-tion mechanisms of the boom and stick. The proposed methodology for determining the operational parameters of the main mechanisms will allow us to estimate the range of changes in the power parameters implemented on the cutting edge of the bucket in the working area and to identify the relationship between active and reactive loads in the mechanisms due to the serial connection of hydromechanical units.

Increasing in wear resistance of excavating machine elements

The relevance of the search for solutions to increase the wear resistance of bucket teeth of excavating machine type front shovel is analyzed. The reasons for the wear of the teeth are considered. It is determined that when excavating machines work for rocks of VIII and IX categories, impact-abrasive wear of the inner side of the teeth and abrasive external wear occurs. It is proved that the cold-work hardening of Hadfield steel (the teeth material), which occurs during the excavating machine teeth work in the rocks of VIII and IX categories, reduces the impact-abrasive wear rate on the inner side of the teeth and does not affect the abrasive wear of the outer. The methods for thermomechanical treatment of the outer side of the excavating machine tooth is proposed. It can increase the wear resistance of Hadfield steel (110G13L) up to 1.7 times and lead to the self-sharpening effect of the tooth due to equalization of the wear rate of the outer and inner parts of the tooth. The efficiency factor of thermomechanical treatment to reduce the of abrasive wear rate of Hadfield steel is experimentally proved.

About the use of 110G13L steel as a material for the excavator bucket teeth

The causes of failure of the bucket teeth of the excavator during excavations in rocks are analyzed in the article. It is shown that the most typical cause of failure of bucket teeth is wear of teeth. The wear with soft rocks (less than 1100 HV) which hardness is lower than the hardness of steel in the cold-work hardened state, a preliminary cold-work hardening can essentially (up to 10 times) increase the material wear resistance. The wear with rocks, having greater hardness with hardness of ~1250 HV, the cold-work hardening do not lead to increase of the Hadfield steel wear resistance.