Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors

Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental protection.However,the placement of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine slides.Historical incidents have highlighted the substantial damage to pipelines due to slides.Specifically,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant threat.Accurately assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline safety.This study aimed to provide a comprehensive overview of recent advancements in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact forces.These factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of pipelines.Additionally,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with pipelines.Building upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive understanding of these results is essential for the sustainable development of deep-sea pipeline projects associated with seabed resource development and the implementation of disaster prevention measures.

Review and propositions for the sliding/impact wear behavior in a contact interface

A thermal-solid-liquid complex operational environment induces structural interface developing a typical coupling sliding/impact wear behavior.It results in contact damage until systems fail,which may cause significant economic losses and catastrophic consequences.The key point of solving this problem is to reveal the coupling damage mechanism of the sliding/impact behavior in typical systems and life characterization under a complicate evolving environment.This has been a hot topic in the area of mechanical reliability.The main work in this paper can be concluded as follows.Firstly,the main industries in which the"sliding/impact behavior"takes place have been introduced.Then,existing studies on the wear mechanism and degree analysis are presented,which includes surface morphology analysis,wear debris analysis,and wear degree measurement.Meanwhile,existing problems in theoretical modeling and experiments in current research are summarized,so as to point out a bright direction for future research on wear prediction.They include interface contact modeling,mathematic coupling mechanism modeling,wear equation establishment,and wear life characterization,which can provide some new ideas for improving the existing studies on the sliding/impact wear behavior.

Dry sliding wear behavior of cast Mg-11Y-5Gd-2Zn magnesium alloy

Dry sliding wear tests on as-cast and cast＋T6 Mg-11Y-5Gd-2Zn magnesium alloys were performed using a ball-on-plate configuration. The wear rates were measured within a load range of 3-15 N, sliding speed range of 0.03-0.24 m/s, test temperature range of 25-200 °C and at a constant sliding distance of 400 m. The wear tracks, worn surfaces and wear debris of the alloys were analyzed using scanning electron microscope （SEM）. The results show that the wear rate of the alloys increases almost linearly with increasing applied load and decreases with increasing sliding speed. The wear rate of the as-cast alloy is higher than that of the cast＋T6 alloy. The amount of Mg12Y1Zn1 phase, surface oxidation and retained wear debris affect the wear rate. The dominant wear mechanisms under the test condition are abrasion and plastic deformation.

Microstructure and dry sliding wear behavior of cast Al-Mg_2Si in-situ metal matrix composite modified by Nd

The microstructure and dry sliding wear behav- ior of cast Al-18 wt% MgaSi in-situ metal matrix com- posite modified by Nd were investigated. Experimental results show that, after introducing a proper amount of Nd, both primary and eutectic Mg2Si in the Al-18 wt% Mg2Si composite are well modified. The morphology of primary Mg2Si is changed from irregular or dendritic to polyhedral shape, and its average particle size is signifi- cantly decreased. Moreover, the morphology of the eutectic MgzSi phase is altered from flake-like to very short fibrous or dot-like. The wear rates and friction coefficient of the composites with Nd are lower than those without Nd. Furthermore, the addition of 0.5 wt% Nd changes the wear mechanism of the composite from the combination of abrasive, adhesive, and delamination wear without Nd into a single mild abrasion wear with 0.5 wt% Nd.

Wear behavior of bainite ductile cast iron under impact load

The dry impact wear behavior of bainite ductile cast iron was evaluated under three different impact loads for 30000 cycles. The strain-hardening effects beneath the contact surfaces were analyzed according to the surfaces＇ micro-hardness profiles. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to observe the wom surfaces. The results indicated that the material with the highest hardness was the one continuously cooled at 20℃, which exhibited the lowest wear rate under each set of test conditions. The hardness of the worn surface and the thickness of the hardened layer increased with the increases in impact load and in the number of test cycles. The better wear performance of the sample cooled at 20℃ is attributed to its finer microstructure and superior mechanical properties. All the samples underwent the transformation induced plasticity （TRIP） phenomenon after impact wear, as revealed by the fact that small amounts of retained austenite were detected by XRD.

Experimental study ofcasing wear under impact-sliding conditions

Theoretical analysis and field monitoring show that lateral vibration has very important effect on casing wear in deep & ultra-deep well drilling. The wear mechanism of casing under impact-sliding work conditions has been investigated and many experiments have been completed with a newly developed full-scale casing wear test machine. Test results present that adhesion wear, contact fatigue, and grinding abrasion are the main wear mechanisms under impact-sliding test conditions. The friction coefficient and linear wear rate of the casing rise obviously with an increase in impact load. And the larger the impact load, the rougher the worn surface of the casing. The linear wear rate decreased slightly but the average friction coefficient increased slightly with an increase in impact frequency under an impact load of 2,500 N. Both the linear wear rate of the casing and the average friction coefficient increased substantially with an increase in impact frequency under an impact load of 4,000 N. Under lower impact load conditions, grinding abrasion and contact fatigue are the main mechanisms of casing wear; under higher impact load conditions, adhesion wear and contact fatigue are the main mechanisms of casing wear.

Influence of Heat Treatment on Microstructure and Sliding Wear Behavior of Fe-Al/WC Composite Coatings

An experimental study has been carried out to investigate the influence of heat treatment at 300 ℃,450 ℃,550 ℃,650 ℃ and 800 ℃ on the microstructure and sliding wear behavior of Fe Al/WC intermetallic composite coatings produced by high velocity arc spraying (HVAS) and cored wires. The result shows, the main phases in both as sprayed and heat treated Fe Al/WC composite coatings are iron aluminide intermetallics (Fe 3Al+FeAl) and α as well as a little oxide (Al 2O 3) and carbides (WC, W 2C, Fe 2W 2C and Fe 6W 6C). After heat treated at 450-650 ℃, dispersion strengthening of Fe 2W 2C and Fe 6W 6C will lead to a rise in microhardness of the coatings. The microhardness is likely to be the most important factor which influences the sliding wear behavior of the coatings. Increasing the microhardness through heat treatment will improve the sliding wear resistance of the Fe Al/WC composite coatings.

超声表面滚压工艺影响镍基690合金冲-切磨损行为的研究

通过超声表面滚压技术(USRP)改善镍基690合金表面的粗糙度和硬化层,并探究该工艺对其冲-切磨损行为的影响机理.首先,采用USRP对镍基690合金表面进行强化处理,然后,基于可控能量式冲-切磨损试验装置,探究镍基690合金强化前后在不同冲-切变量下其磨损界面的动态响应行为与损伤机理.得出了USRP工艺可有效降低磨损界面的摩擦力和摩擦系数,降低冲切能耗,进而减少材料的磨损程度,此外,冲击或切向滑动速度的增加均会导致磨损界面所受冲击力和摩擦力的增大,并降低动能吸收率.

Size Effect of Impact Abrasive Particles on Wear and Surface Hardening Behavior of High‑Manganese Steel

The size effect of impact abrasive particles on wear and surface hardening behavior of high-manganese steel was studied.Impact wear tests were carried out on MLD-10 tester with abrasive particle sizes of 6.0–0.75 mm,respectively.The results showed that the impact wear behavior and surface hardening mechanism of high-manganese steel were affected by the size of abrasive particles.A critical size of abrasive particle might exhibit to distinguish the impact wear behavior.When the abrasive particle size was larger than 0.75 mm,the wear mass loss generally showed a decreasing trend with the decrease of the abrasive particle size.Dislocation strengthening and mechanical twinning contributed to the good work hardening behavior.However,effective surface hardening layer could not be formed for sample tested with particle size of 0.75 mm and the wear mass loss was the highest among all the conditions.The weak hardening effect led to the sharp increase of the wear mass loss.Press-in abrasives could be observed on the wear surface when the abrasive particle size was larger than 0.75 mm.The press-in abrasives were peeled off from the wear surface and broken,leaving deep grooves and peeling pits.Material exchange with the sample would occur with the flow of abrasives.A large area of furrow was formed on the wear surface.For particle size of 0.75 mm,aggregated abrasives formed a dynamic buffer layer on the surface and the stress distribution was more even.The formation of buffer layer would lower the effect of the impact load and the work hardening effect could not be fully activated.The mutual extrusion among the abrasives,friction wheel and sample caused plastic deformation of the worn surface during impact test.The present study would help guiding to select the application field of high-manganese steel more precisely.

Dry Friction Characteristics of Ti-6Al-4V Alloy under High Sliding Velocity

Tribological behaviours of Ti-6Al-4V alloy pins sliding against GCr15 steel discs over a range of contact pressures （0.33-1.33 MPa） and sliding velocities （30-70 m/s） were investigated using a pin-on-disc tribometer under unlubricated conditions. The wear mechanisms and the wear transition were analyzed based on examinations of worn surfaces using SEM, EDS and XRD. When the velocity increases, the friction coefficient and the wear rate of the Ti-6Al-4V alloy show typical transition features, namely, the critical values of sliding velocities for 0.33 and 0.67 MPa are 60 and 40 m/s, respectively. The experimental results reveal that the tribological behaviours of Ti-6Al-4V alloys are controlled by the thermal-mechanical effects, which connects with the friction heat and hard particles of the pairs. A tribolayer containing mainly Ti oxides and V oxides is formed on the worn surface of Ti-6Al-4V alloy.

盾构滚刀材料表面镍基碳化钨涂层摩擦学性能研究

目的盾构滚刀磨损是盾构施工中最常见的问题之一,为减缓刀具的剧烈磨损、延长刀具的使用寿命,采用等离子堆焊工艺在盾构滚刀表面制备镍基碳化钨涂层以强化滚刀性能,基于盾构滚刀服役的真实工况,研究滚刀涂层的摩擦学性能及其合理的评价方式。方法对镍基碳化钨涂层在往复滑动、冲滑复合(冲击+滑动)两种相对运动模式下进行摩擦磨损试验研究。结果制备镍基碳化钨涂层后可提高滚刀的耐磨性。往复滑动磨损后,镍基碳化钨涂层的磨痕宽度为0.42 mm,而H13钢的磨痕宽度达到0.78 mm,镍基碳化钨涂层的抗冲滑性能也明显优于H13钢。两种相对运动模式下镍基碳化钨涂层均主要承受磨粒磨损,但往复滑动模式下涂层存在局部剥落,而冲滑复合模式下则伴随一定的粘着磨损。结论在两种相对运动模式下,镍基碳化钨涂层表面的高硬度碳化钨颗粒都可阻止磨粒对较软镍基合金区域的切削与碰撞。相较往复滑动模式,冲滑复合模式下镍基碳化钨涂层要承受冲击和滑动的耦合作用,涂层的磨痕特征以及损伤形式都有明显的不同。采用冲滑复合运动模式的摩擦磨损试验能对盾构滚刀刀圈的摩擦学性能进行更全面、合理的研究及评价。

铜石墨合金材料在载流条件下的摩擦磨损行为研究

采用冷压烧结粉末冶金法,以300 MPa的压力进行初压,在氢气保护气氛下于烧结温度为950℃,3 h下烧结,然后冷却至室温后再以300 MPa的压力进行复压制备出铜石墨合金材料.通过电滑动磨损试验及扫描电子显微镜分析等方法研究了铜石墨合金材料的磨损性能,探讨其磨损机制.结果表明:在试验参数范围内,试样的磨损量随着试验载荷、速度及电流密度的增加而增大;在载流条件下电流产生的电弧热是其磨损量增加的主要因素;石墨和铅以单质形式存在有利于摩擦副之间的润滑和提高其耐磨性能;合金的磨损机制主要为磨粒磨损、电侵蚀磨损和黏着磨损.

Ti6Al4V合金的磨损行为和磨损机制

采用销-盘式高温磨损试验机对Ti6Al4V合金在20～400℃进行干滑动摩擦磨损实验,研究了Ti6Al4V合金的磨损行为并探讨了其磨损机制。结果表明:25℃时,合金的磨损量随载荷的增加而逐渐升高;200℃时的磨损量略高于25℃,但当载荷高于200N时,磨损量急剧升高。当温度为400℃、载荷在50～100N时,磨损量降低且达到最低值,随后在100～200N之间磨损量略有升高,200N以后磨损量急剧升高。25℃和200℃下磨损机制主要为黏着磨损和磨粒磨损;400℃、载荷为100～200N时磨损机制为氧化轻微磨损。研究发现,磨损过程中形成机械混合层,当400℃,载荷为100～200N时机械混合层中出现氧化物Ti8O15和TiO2,这样硬的机械混合层具有显著地减磨作用。

全尺寸石油套管冲击滑动复合磨损试验机的研制

介绍了一种新型石油套管磨损试验机的工作原理和检测方法,该试验机能模拟存在钻井液介质润滑条件时钻杆接头外壁与套管内壁之间以恒定加载、脉动加载或冲击加载工况下的套管磨损状况。试验前钻杆接头试件被固定在一个可上下直线运动的滑动平台上,固定不动的套管试件有间隙地套住钻杆接头试件。试验时利用变频调速电机驱动钻杆接头试件旋转,同时由液压伺服系统推动滑动平台下行带动钻杆接头试件外壁挤压套管试件内壁实现恒定或脉动加载,或者由偏心轮机构驱动滑动平台先上行后下落来带动钻杆接头试件对套管内壁进行冲击。在数据采集方面该试验机综合利用多种传感检测技术、数据采集和软件处理方法实现了对试件的线性磨损量、接触载荷、摩擦因数和近摩擦表面温度等摩擦学参数的在线测试。初步试验结果表明可利用该试验机对套管磨损问题进行系统的试验研究,从而为深入研究套管磨损机制提供技术支持。

高速干摩擦条件下铝基复合材料的摩擦磨损行为研究

在MMS-1G型高速干滑动摩擦磨损试验机上,采用铝基复合材料和蠕墨铸铁作为销试样,研究了速度和接触压力对摩擦副摩擦磨损特性的影响.结果表明:摩擦副的摩擦磨损特性受控于所产生的摩擦热、材料的导热能力以及材料保持一定塑性变形抗力的温度条件三者之间的耦合作用;随着速度与接触压力的增加,摩擦副的摩擦系数显著降低;不同材料表现出不同的磨损行为;接触压力愈高,材料的摩擦磨损性能差异愈小;在本文试验条件下,当摩擦速度较低(<100m/s)时,蠕墨铸铁表现出良好的摩擦磨损特性,而速度较高(>100m/s)时,铝基复合材料表现出较优良的摩擦磨损性能.

表面纳米化中碳钢在干摩擦条件下的摩擦磨损性能研究

采用高能喷丸方法对45^#钢进行表面纳米化处理，在环-盘摩擦磨损试验机上评价表面纳米化处理45^#钢与TIO钢摩擦副在干摩擦条件下的摩擦磨损试验，通过分析其磨损表面形貌探讨表面纳米化对中碳钢磨损行为的影响．结果表明：在载荷为10—60N条件下，表面纳米化中碳钢的摩擦系数较处理前有所降低；在载荷为10—40N时，其磨损质量损失较处理前有所降低；表面纳米化能够减弱中碳钢的疲劳磨损效应，提高中碳钢的摩擦磨损性能．

纳米Al_2O_3颗粒含量对复合镀层组织和滑动磨损行为的影响

采用电刷镀技术在45钢表面制备了纳米Al2O3 颗粒增强镍基复合镀层,研究了纳米Al2O3 颗粒在镀液中的含量对镀层的组织、力学性能和摩擦学性能的影响,并分析探讨了影响机理。结果表明,随着镀液中纳米Al2O3 颗粒含量的增加,复合镀层的组织趋于细化,在含量为20g/L时复合镀层的硬度和耐磨性出现极值,其磨损机制也随之发生改变,这与纳米Al2O3 颗粒在复合镀层中的含量和分布状态密切相关。

在加载电流作用下Cr对Cu-Ag合金磨损性能的影响

通过电滑动磨损试验、扫描电子显微镜和透射电子显微镜分析等方法,研究了在加载电流作用下微量C r对4种不同成分Cu-A g-C r合金磨损性能的影响,探讨其电磨损机理.结果表明:Cu-A g合金的磨损率随着C r含量增加而减小;不同成分合金的磨损率均随着电流和滑动距离增大而逐渐增大;由于加入微量C r在合金中形成弥散细小的析出相,在相同试验条件下,添加C r的合金磨损性能明显优于Cu-A g合金;合金的磨损机制主要为粘着磨损、磨粒磨损和电侵蚀磨损.

热处理对铁铝涂层相组成及滑动磨损性能的影响

采用粉芯丝材和高速电弧喷涂技术得到的铁铝金属间化合物涂层 ,研究了 5 5 0℃和 80 0℃热处理对涂层相组成及滑动磨损性能的影响。结果表明 ,涂层的主要组成相是铁铝金属间化合物 (FeAl和Fe3 Al)和α Fe ,另有少量的Al2 O3 和Al。热处理后 ,一部分Fe3 Al将转变成FeAl,对涂层的显微硬度有明显的影响。剥层磨损是铁铝涂层的主要磨损机理。通过热处理提高涂层的显微硬度 。

AZ80镁合金表面冷喷涂316L涂层的微观组织及性能

为了提高AZ80镁合金的耐磨及耐腐蚀性能,利用冷喷涂技术在其表面制备了316L不锈钢涂层。采用X射线衍射仪及扫描电镜对涂层的相结构、微观组织及粒子与基板的碰撞行为进行了分析,采用万能力学试验机测试了涂层的结合强度及内聚强度,并分别测试了涂层与块体的摩擦磨损及电化学腐蚀性能。结果表明:冷喷涂316L粒子与镁合金基板的碰撞行为主要呈现两种方式,一种是粒子在镁合金基板表面产生冲蚀坑,未能形成有效结合,另一种是粒子以球形方式嵌入镁合金基板内部,基板在两种碰撞行为中都形成射流,结合机理主要是机械咬合。316L涂层磨损率为1.16×10^(-4) mm^3/(N·m),其耐磨性较镁合金提高了8倍,涂层的自腐蚀电流较镁合金基体降低了4个数量级,能够有效保护镁合金基板。