2025年事業(yè)單位工勤技能-北京-北京鑄造工一級(jí)（高級(jí)技師）歷年參考題庫含答案解析(5套)2025年事業(yè)單位工勤技能-北京-北京鑄造工一級(jí)（高級(jí)技師）歷年參考題庫含答案解析(篇1)【題干1】砂型鑄造中，涂料的主要作用不包括以下哪項(xiàng)？A.提高型腔表面光潔度B.防止金屬液滲漏C.降低砂型收縮率D.抵抗金屬液沖刷【參考答案】C【詳細(xì)解析】涂料的主要功能是形成保護(hù)膜，防止金屬液滲漏（B）、抵抗沖刷（D）并提高表面光潔度（A）。砂型收縮率與涂料無直接關(guān)聯(lián)，需通過合金熔煉和冷卻控制（C為干擾項(xiàng)）。【題干2】鑄鐵件熱處理中，退火的主要目的是消除哪種缺陷？A.殘余應(yīng)力B.晶粒粗大C.表面氧化D.內(nèi)部縮松【參考答案】A【詳細(xì)解析】退火通過緩慢冷卻消除鑄件內(nèi)應(yīng)力（A），改善機(jī)械性能。正火用于細(xì)化晶粒（B），淬火強(qiáng)化組織（C為表面處理缺陷）?？s松需通過澆注工藝優(yōu)化解決（D）?！绢}干3】鋁合金鑄造時(shí)，熔煉溫度過高會(huì)導(dǎo)致哪種典型缺陷？A.氣孔B.縮孔C.熱裂D.晶粒粗大【參考答案】C【詳細(xì)解析】鋁合金液過熱易引發(fā)熱裂（C），因高溫下晶界弱化，冷卻時(shí)收縮應(yīng)力導(dǎo)致開裂。氣孔（A）與熔煉氣體含量相關(guān)，縮孔（B）源于凝固收縮，晶粒粗大（D）與冷卻速度有關(guān)。【題干4】砂型鑄造中，分型面設(shè)計(jì)不當(dāng)可能引發(fā)哪種缺陷？A.飛邊B.縮松C.裂紋D.澆不足【參考答案】B【詳細(xì)解析】分型面設(shè)計(jì)缺陷會(huì)導(dǎo)致鑄件內(nèi)部縮松（B），因金屬液未完全充滿型腔。飛邊（A）源于澆注系統(tǒng)開設(shè)不當(dāng)，裂紋（C）與殘余應(yīng)力相關(guān)，澆不足（D）因金屬液量不足?！绢}干5】鑄鋼件熱處理時(shí)，正火工藝適用于哪種牌號(hào)的鋼？A.ZG45B.ZG55C.ZCuSn10P1D.QT500-7【參考答案】A【詳細(xì)解析】正火用于過共析鋼（如ZG45）改善切削加工性（A）。ZG55為亞共析鋼需退火（B）。銅合金（C）熱處理以去應(yīng)力為主，球墨鑄鐵（D）需退火或正火消除粗片狀石墨?！绢}干6】熔模鑄造中，粘結(jié)劑的作用不包括哪項(xiàng)？A.連接熔模與型殼B.提高型殼強(qiáng)度C.防止金屬液侵蝕D.增加鑄件致密度【參考答案】D【詳細(xì)解析】粘結(jié)劑（如水玻璃）主要連接熔模與型殼（A），增強(qiáng)型殼強(qiáng)度（B），并隔絕金屬液腐蝕（C）。鑄件致密度由合金流動(dòng)性決定（D）。【題干7】鑄造缺陷中，冷隔的成因與哪種因素直接相關(guān)？A.澆注速度不足B.熔煉溫度過低C.模型排氣不良D.合金凝固區(qū)間寬【參考答案】A【詳細(xì)解析】冷隔（A）因澆注速度不足導(dǎo)致金屬液斷流，與模型排氣（C）和凝固區(qū)間（D）無關(guān)。熔煉溫度低（B）易產(chǎn)生氣孔而非冷隔。【題干8】鑄件熱處理時(shí)，時(shí)效強(qiáng)化的主要機(jī)制是？A.晶界滑移B.晶粒細(xì)化C.析出強(qiáng)化相D.固溶強(qiáng)化【參考答案】C【詳細(xì)解析】鋁合金等鑄件時(shí)效強(qiáng)化（C）通過析出納米級(jí)強(qiáng)化相（如Al2Cu）提升強(qiáng)度。晶界滑移（A）對(duì)應(yīng)高溫變形，晶粒細(xì)化（B）需通過熱處理或細(xì)化劑實(shí)現(xiàn)，固溶強(qiáng)化（D）需快速冷卻?！绢}干9】砂型鑄造中，使用型砂的含水率過高會(huì)導(dǎo)致哪種缺陷？A.砂眼B.沙眼C.熱裂D.澆不足【參考答案】B【詳細(xì)解析】型砂含水率過高（B）會(huì)降低粘結(jié)性，金屬液沖刷形成沙眼（孔徑＞1mm）。砂眼（A）為局部砂粒未粘結(jié)，熱裂（C）與應(yīng)力相關(guān)，澆不足（D）因金屬液量不足?！绢}干10】鑄鐵件平衡組織中的石墨形態(tài)為？A.晶界呈蠕蟲狀B.呈片狀分布于基體C.呈球狀或短棒狀D.均勻分布于晶界【參考答案】A【詳細(xì)解析】灰鑄鐵平衡組織石墨為片狀（B為灰口鑄鐵非平衡態(tài)），蠕蟲狀（A）為球墨鑄鐵特征。球狀（C）為可鍛鑄鐵，均勻分布（D）為白口鑄鐵?！绢}干11】熔煉鑄鐵時(shí)，硅鐵加入量過少會(huì)導(dǎo)致哪種缺陷？A.白口傾向增大B.碳當(dāng)量升高C.石墨片粗大D.硬度降低【參考答案】A【詳細(xì)解析】硅鐵（FeSi）減少會(huì)降低碳當(dāng)量（B需碳量增加），增大白口傾向（A）。石墨片粗大（C）與冷卻速度相關(guān)，硬度降低（D）因合金成分變化。【題干12】鑄造鋁合金的常見缺陷是？A.氣孔B.縮松C.冷隔D.熱裂【參考答案】A【詳細(xì)解析】鋁合金熔煉中易產(chǎn)生氣孔（A），因Al-Si合金熔體中氫含量高。縮松（B）多因澆注系統(tǒng)設(shè)計(jì)不當(dāng)，冷隔（C）與澆注速度相關(guān)，熱裂（D）需通過熱處理消除。【題干13】鑄鋼件正火工藝的冷卻速率應(yīng)？A.與退火相同B.介于退火與淬火之間C.快于淬火D.等于退火【參考答案】B【詳細(xì)解析】正火冷卻速率（B）介于退火（緩慢）與淬火（快速）之間，用于細(xì)化晶粒消除網(wǎng)狀滲碳體。鑄鋼退火（A/D）用于均勻組織，淬火（C）強(qiáng)化組織。【題干14】砂型鑄造涂料中，石墨粉的作用是？A.提高涂料附著力B.增加涂料滲透性C.改善涂料熱穩(wěn)定性D.降低涂料干燥速度【參考答案】C【詳細(xì)解析】石墨粉（C）可提高涂料熱穩(wěn)定性，防止高溫下涂料燒損。附著力（A）靠粘結(jié)劑實(shí)現(xiàn)，滲透性（B）與涂料成分相關(guān)，干燥速度（D）由溶劑種類決定?！绢}干15】鑄造缺陷中，夾渣的成因與哪種工藝參數(shù)相關(guān)？A.澆注溫度B.模型排氣性C.熔煉時(shí)間D.合金粘度【參考答案】A【詳細(xì)解析】夾渣（A）因澆注溫度過高導(dǎo)致熔體粘度降低，夾雜物（如氧化物）無法上浮。模型排氣性（B）影響氣孔而非夾渣，熔煉時(shí)間（C）影響成分均勻性，合金粘度（D）與夾雜物上浮力相關(guān)?！绢}干16】球墨鑄鐵熱處理中，退火工藝的主要目的是？A.消除內(nèi)應(yīng)力B.?；瘽B碳體C.細(xì)化石墨D.強(qiáng)化基體【參考答案】B【詳細(xì)解析】球墨鑄鐵退火（B）通過石墨化反應(yīng)將滲碳體（Fe3C）轉(zhuǎn)化為石墨，改善切削加工性。消除內(nèi)應(yīng)力（A）需去應(yīng)力退火，細(xì)化石墨（C）需孕育處理，強(qiáng)化基體（D）需淬火加回火。【題干17】鑄造鋁合金時(shí)，熔煉保溫時(shí)間不足會(huì)導(dǎo)致哪種缺陷？A.氣孔B.縮孔C.過熱組織D.鑄件變形【參考答案】C【詳細(xì)解析】保溫時(shí)間不足（C）會(huì)導(dǎo)致熔體過熱，晶粒粗大并產(chǎn)生異常組織。氣孔（A）與熔煉氣體含量相關(guān)，縮孔（B）因澆注系統(tǒng)設(shè)計(jì)不當(dāng)，鑄件變形（D）與冷卻收縮有關(guān)?！绢}干18】鑄鐵件熱處理中，淬火后回火的主要目的是？A.提高表面硬度B.消除殘余應(yīng)力C.增加耐磨性D.細(xì)化晶?！緟⒖即鸢浮緽【詳細(xì)解析】鑄鐵淬火后回火（B）主要用于消除殘余應(yīng)力并調(diào)整硬度。提高表面硬度（A）需表面淬火，增加耐磨性（C）需滲碳處理，細(xì)化晶粒（D）需正火或退火?！绢}干19】砂型鑄造中，型砂配比中硅藻土的加入量過高會(huì)導(dǎo)致哪種問題？A.型砂透氣性降低B.型砂強(qiáng)度不足C.涂料干燥困難D.鑄件尺寸精度下降【參考答案】A【詳細(xì)解析】硅藻土（A）過多會(huì)堵塞型砂孔隙，降低透氣性。強(qiáng)度不足（B）需添加粘結(jié)劑，涂料干燥（C）與溶劑種類相關(guān)，鑄件尺寸（D）受模型精度影響?！绢}干20】鑄造缺陷中，流渣的成因與哪種工藝相關(guān)？A.澆注溫度B.模型精度C.熔煉純凈度D.冷卻速度【參考答案】A【詳細(xì)解析】流渣（A）因澆注溫度過高導(dǎo)致熔體流動(dòng)性增強(qiáng)，卷入型腔氣體或雜質(zhì)。模型精度（B）影響鑄件表面，熔煉純凈度（C）影響氣孔，冷卻速度（D）影響組織與缺陷類型。2025年事業(yè)單位工勤技能-北京-北京鑄造工一級(jí)（高級(jí)技師）歷年參考題庫含答案解析(篇2)【題干1】砂型鑄造中，哪種缺陷主要由金屬液與型砂間氣體未完全排出導(dǎo)致？【選項(xiàng)】A.夾渣B.氣孔C.裂紋D.縮松【參考答案】B【詳細(xì)解析】氣孔是金屬液中氣體未完全排出形成的孔洞，常見于砂型鑄造中。夾渣由雜質(zhì)混入引起，裂紋因熱應(yīng)力或結(jié)構(gòu)缺陷導(dǎo)致，縮松是金屬凝固收縮形成的。題目考察鑄造缺陷成因，B為正確答案。【題干2】鑄件熱處理中，退火的主要目的是什么？【選項(xiàng)】A.提高硬度B.細(xì)化晶粒C.消除內(nèi)應(yīng)力D.增加塑性【參考答案】B【詳細(xì)解析】退火通過高溫緩慢冷卻，使組織均勻化并細(xì)化晶粒，改善機(jī)械性能。正火側(cè)重提高強(qiáng)度，淬火用于提高硬度和強(qiáng)度，回火調(diào)整殘余應(yīng)力。本題重點(diǎn)考察熱處理工藝核心目的，B為正確答案。【題干3】鑄鐵件采用球化退火處理時(shí)，球化劑通常選用哪種物質(zhì)？【選項(xiàng)】A.鋁B.鎂C.硅D.鈦【參考答案】A【詳細(xì)解析】球化退火使用硅鐵或鋁作為球化劑，促使石墨呈球狀析出，提高鑄鐵切削性能和抗應(yīng)力能力。鎂和鈦多用于鑄鋼處理，硅單獨(dú)使用效果有限。本題考察球化退火關(guān)鍵材料，A為正確答案?！绢}干4】砂型鑄造中，型砂配比中若黏土含量過高會(huì)導(dǎo)致什么問題？【選項(xiàng)】A.型砂強(qiáng)度不足B.透氣性太好C.表面粗糙度低D.干燥時(shí)間延長(zhǎng)【參考答案】A【詳細(xì)解析】黏土含量過高會(huì)降低型砂透氣性，同時(shí)使砂型強(qiáng)度不足，易塌箱。高透氣性需適當(dāng)減少黏土，表面粗糙度與黏土含量無關(guān)，干燥時(shí)間受濕度影響更大。本題重點(diǎn)考察型砂配比控制要點(diǎn)，A為正確答案?！绢}干5】鑄鋼件澆注系統(tǒng)設(shè)計(jì)時(shí)，直澆道截面面積與鑄件質(zhì)量的關(guān)系如何？【選項(xiàng)】A.等比增大B.等比縮小C.常數(shù)關(guān)系D.成反比關(guān)系【參考答案】A【詳細(xì)解析】直澆道截面積需與鑄件質(zhì)量成正比，確保金屬液流速和充型能力。等比縮小會(huì)導(dǎo)致流速不足，等比增大造成浪費(fèi)，常數(shù)關(guān)系無法適應(yīng)不同鑄件尺寸。本題考察澆注系統(tǒng)設(shè)計(jì)比例關(guān)系，A為正確答案?！绢}干6】鑄件表面缺陷中，熱節(jié)區(qū)的特征是？【選項(xiàng)】A.金屬液堆積不均B.晶粒粗大C.孔洞密集D.表面氧化嚴(yán)重【參考答案】B【詳細(xì)解析】熱節(jié)區(qū)因金屬液冷卻快形成粗大晶粒，常見于鑄件厚大部位或激冷劑使用過量處?？锥疵芗酁闅饪谆蚩s松，氧化嚴(yán)重與澆注溫度或模具材料相關(guān)。本題重點(diǎn)考察鑄造缺陷類型與特征，B為正確答案?！绢}干7】砂型鑄造中，型砂回用前需要進(jìn)行的工序是？【選項(xiàng)】A.燒結(jié)B.濕式破碎C.酸洗D.熱壓成型【參考答案】A【詳細(xì)解析】型砂回用需先進(jìn)行高溫?zé)Y(jié)，去除水分和有機(jī)物，恢復(fù)顆粒間黏結(jié)力。濕式破碎用于處理廢砂，酸洗針對(duì)金屬表面處理，熱壓成型用于制備新砂。本題考察型砂再生工藝，A為正確答案?！绢}干8】鑄件尺寸精度控制中，以下哪種方法屬于機(jī)械加工補(bǔ)償法？【選項(xiàng)】A.調(diào)整模具間隙B.選用高精度機(jī)床C.增加余量D.優(yōu)化冷卻工藝【參考答案】B【詳細(xì)解析】機(jī)械加工補(bǔ)償法指通過機(jī)床精度提升來保證鑄件尺寸，如使用五軸聯(lián)動(dòng)加工中心。調(diào)整模具間隙屬于鑄造工藝控制，增加余量是鑄造補(bǔ)償法，冷卻工藝影響鑄造缺陷而非加工精度。本題重點(diǎn)區(qū)分鑄造與加工補(bǔ)償方法，B為正確答案?！绢}干9】球墨鑄鐵的孕育處理最佳溫度范圍是？【選項(xiàng)】A.800-900℃B.950-1050℃C.700-800℃D.650-750℃【參考答案】A【詳細(xì)解析】孕育處理需在鐵液接近熔點(diǎn)時(shí)加入孕育劑，800-900℃為球化反應(yīng)最佳溫度范圍，過高會(huì)導(dǎo)致石墨球化不完全，過低影響擴(kuò)散速度。其他選項(xiàng)溫度范圍與孕育工藝不符。本題考察球墨鑄鐵處理關(guān)鍵參數(shù)，A為正確答案?！绢}干10】鑄造工藝圖中，模數(shù)（模數(shù)）的確定依據(jù)是？【選項(xiàng)】A.鑄件最大尺寸B.鑄件壁厚C.模具制造精度D.金屬液收縮率【參考答案】D【詳細(xì)解析】模數(shù)是模具尺寸與鑄件尺寸的比值，用于控制金屬液收縮率導(dǎo)致的尺寸偏差。鑄件最大尺寸決定模具總體積，壁厚影響局部收縮，制造精度影響加工誤差。本題重點(diǎn)考察模具設(shè)計(jì)核心參數(shù)，D為正確答案?！绢}干11】鑄件熱處理中，正火與退火的主要區(qū)別在于？【選項(xiàng)】A.加熱溫度B.冷卻速度C.保溫時(shí)間D.工藝設(shè)備【參考答案】B【詳細(xì)解析】正火采用空冷（冷卻速度較快），退火采用爐冷（冷卻速度慢）。加熱溫度和保溫時(shí)間兩者相近，工藝設(shè)備無本質(zhì)差異。本題重點(diǎn)考察熱處理工藝關(guān)鍵差異，B為正確答案?！绢}干12】砂型鑄造中，芯砂的透氣性要求比面砂高多少倍？【選項(xiàng)】A.2-3倍B.3-5倍C.5-8倍D.8-10倍【參考答案】C【詳細(xì)解析】芯砂需保證金屬液穿透能力，透氣性要求為面砂的5-8倍。2-3倍適用于簡(jiǎn)單芯子，3-5倍用于中等復(fù)雜芯，8-10倍對(duì)應(yīng)高復(fù)雜度芯子。本題考察鑄造工藝參數(shù)對(duì)比，C為正確答案?！绢}干13】鑄鋼件鑄造缺陷中，冷隔的成因是？【選項(xiàng)】A.金屬液溫度不足B.模型強(qiáng)度不足C.澆注系統(tǒng)堵塞D.金屬液黏度過高【參考答案】C【詳細(xì)解析】冷隔由澆注系統(tǒng)堵塞導(dǎo)致金屬液斷流形成，常見于直澆道或冒口堵塞。溫度不足會(huì)導(dǎo)致凝固過早，模型強(qiáng)度不足引發(fā)塌箱，黏度過高影響流動(dòng)性。本題重點(diǎn)考察鑄造缺陷成因，C為正確答案。【題干14】鑄造工藝中，采用階梯式澆注系統(tǒng)的目的是？【選項(xiàng)】A.提高金屬液純凈度B.均勻充型C.降低澆注溫度D.減少收縮應(yīng)力【參考答案】B【詳細(xì)解析】階梯式澆注通過多個(gè)澆口同時(shí)澆注，使金屬液沿鑄件高度均勻上升，避免局部過熱和流動(dòng)阻力。純凈度與過濾網(wǎng)相關(guān)，澆注溫度與金屬種類有關(guān)，收縮應(yīng)力通過冒口補(bǔ)縮控制。本題重點(diǎn)考察澆注系統(tǒng)功能，B為正確答案?！绢}干15】鑄件表面粗糙度控制中，以下哪種方法屬于鑄造工藝控制？【選項(xiàng)】A.選用表面光潔的模具B.增加型砂涂料厚度C.調(diào)整金屬液黏度D.提高切削加工精度【參考答案】B【詳細(xì)解析】涂料厚度直接影響鑄件表面光潔度，屬于鑄造工藝控制。模具表面光潔度影響鑄件初始粗糙度，屬于模具設(shè)計(jì)控制。黏度調(diào)整影響流動(dòng)性，加工精度屬于后道工序。本題重點(diǎn)區(qū)分工藝控制方法，B為正確答案?！绢}干16】球墨鑄鐵的孕育處理中，孕育劑加入量通常為鐵液重量的多少？【選項(xiàng)】A.0.5%-1%B.1%-3%C.3%-5%D.5%-8%【參考答案】C【詳細(xì)解析】球墨鑄鐵孕育劑加入量一般為鐵液重量的3%-5%，過高會(huì)導(dǎo)致石墨球化過度，過低影響孕育效果。其他選項(xiàng)范圍與球墨鑄鐵工藝標(biāo)準(zhǔn)不符。本題考察孕育處理關(guān)鍵參數(shù)，C為正確答案?！绢}干17】鑄造工藝中，使用激冷劑的主要目的是？【選項(xiàng)】A.提高金屬液流動(dòng)性B.增加鑄件強(qiáng)度C.減少表面缺陷D.延長(zhǎng)金屬液冷卻時(shí)間【參考答案】C【詳細(xì)解析】激冷劑（如鹽類或金屬溶液）噴灑在鑄型表面，快速冷卻金屬液，使表面形成細(xì)密晶粒，減少氣孔、縮松等缺陷。流動(dòng)性由澆注系統(tǒng)和合金成分決定，強(qiáng)度通過熱處理改善，冷卻時(shí)間與激冷效果相反。本題重點(diǎn)考察激冷劑功能，C為正確答案?！绢}干18】砂型鑄造中，型砂水分過高會(huì)導(dǎo)致什么問題？【選項(xiàng)】A.型砂強(qiáng)度不足B.芯砂透氣性太好C.金屬液氧化嚴(yán)重D.鑄件尺寸精度低【參考答案】A【詳細(xì)解析】水分過高的型砂降低黏結(jié)力和強(qiáng)度，易塌箱或破箱。透氣性改善效果有限，金屬液氧化與澆注溫度相關(guān)，尺寸精度受工藝穩(wěn)定性影響。本題重點(diǎn)考察型砂質(zhì)量控制，A為正確答案?！绢}干19】鑄件熱處理中，淬火后必須立即進(jìn)行的工序是？【選項(xiàng)】A.回火B(yǎng).退火C.正火D.軟化處理【參考答案】A【詳細(xì)解析】淬火后殘余應(yīng)力大，需立即回火以消除應(yīng)力并調(diào)整性能。退火和正火用于非淬火材料，軟化處理多用于金屬冷作硬化。本題重點(diǎn)考察熱處理工序順序，A為正確答案?！绢}干20】鑄造工藝圖中，芯頭尺寸設(shè)計(jì)需考慮哪些因素？【選項(xiàng)】A.芯砂透氣性B.金屬液靜壓力C.芯子制造工藝D.鑄件壁厚【參考答案】B【詳細(xì)解析】芯頭尺寸需滿足金屬液靜壓力要求，防止沖斷芯子。透氣性由芯砂配方控制，制造工藝影響芯頭結(jié)構(gòu)，壁厚決定芯頭支撐需求。本題重點(diǎn)考察芯頭設(shè)計(jì)核心原則，B為正確答案。2025年事業(yè)單位工勤技能-北京-北京鑄造工一級(jí)（高級(jí)技師）歷年參考題庫含答案解析(篇3)【題干1】鑄鐵中硅、錳元素的主要作用是（）A.提高塑性B.增強(qiáng)抗拉強(qiáng)度C.細(xì)化晶粒，降低熱裂傾向D.增加流動(dòng)性【參考答案】C【詳細(xì)解析】硅和錳在鑄鐵中可促進(jìn)石墨化，細(xì)化晶粒，同時(shí)減少石墨與基體之間的應(yīng)力，降低熱裂傾向。選項(xiàng)A錯(cuò)誤因硅含量過高會(huì)降低塑性；選項(xiàng)B片面，硅錳主要提升強(qiáng)度而非抗拉強(qiáng)度；選項(xiàng)D與流動(dòng)性無直接關(guān)聯(lián)?！绢}干2】砂型鑄造中，型砂緊實(shí)度控制在（）范圍較佳A.40%-50%B.50%-60%C.60%-70%D.70%-80%【參考答案】B【詳細(xì)解析】砂型緊實(shí)度需保證型砂強(qiáng)度和透氣性平衡。50%-60%的緊實(shí)度既能有效排出型砂水分，又避免過高導(dǎo)致透氣性不足。選項(xiàng)A過松易塌模，選項(xiàng)C過緊影響排氣，選項(xiàng)D透氣性嚴(yán)重不足?！绢}干3】鑄鋼件采用冒口補(bǔ)縮時(shí)，應(yīng)優(yōu)先考慮（）A.冒口位置靠近厚大斷面B.冒口直徑與鑄件厚度成正比C.冒口高度與鑄件高度相等D.冒口內(nèi)壁涂料厚度不超過3mm【參考答案】A【詳細(xì)解析】冒口補(bǔ)縮需優(yōu)先滿足厚大斷面優(yōu)先凝固原則。選項(xiàng)B比例關(guān)系不成立，冒口直徑與壁厚呈非線性關(guān)系；選項(xiàng)C忽略鑄件收縮率差異；選項(xiàng)D涂料過厚會(huì)阻礙金屬液流動(dòng)。【題干4】球墨鑄鐵中碳當(dāng)量計(jì)算公式為（）A.C%+0.6Si%B.C%+0.4Si%C.C%+0.5Si%D.C%+0.7Si%【參考答案】A【詳細(xì)解析】碳當(dāng)量反映鑄鐵熔點(diǎn)及鑄造性能，球墨鑄鐵碳當(dāng)量公式為C%+0.6Si%。選項(xiàng)B適用于灰鑄鐵，選項(xiàng)C和D為錯(cuò)誤系數(shù)?！绢}干5】下列合金鑄造時(shí)熱裂傾向最高的是（）A.鋁硅合金B(yǎng).銻青銅C.鑄鐵D.球墨鑄鐵【參考答案】B【詳細(xì)解析】銻青銅含銻（Sb）易形成低熔點(diǎn)共晶（Sb-Cu），在冷卻時(shí)產(chǎn)生較大收縮應(yīng)力，導(dǎo)致熱裂傾向最高。選項(xiàng)A鋁硅合金流動(dòng)性好但無顯著脆性；選項(xiàng)C鑄鐵石墨可緩沖應(yīng)力；選項(xiàng)D球墨石墨呈球狀更穩(wěn)定?！绢}干6】鑄造缺陷中，氣孔形成的主要原因是（）A.液態(tài)金屬過熱B.氣體未完全逸出C.模型尺寸誤差D.型砂水分過高【參考答案】B【詳細(xì)解析】氣孔核心原因是氣體（如H2、O2）未完全逸出，凝固過程中氣體被包裹。選項(xiàng)A過熱導(dǎo)致氧化加劇但非直接原因；選項(xiàng)C屬尺寸缺陷；選項(xiàng)D水分高可能產(chǎn)生氣孔但非主因?！绢}干7】砂型鑄造中，使用呋喃樹脂砂的工藝特點(diǎn)不包括（）A.粘結(jié)強(qiáng)度高B.砂粒磨損嚴(yán)重C.透氣性優(yōu)異D.固化時(shí)間短【參考答案】C【詳細(xì)解析】呋喃樹脂砂因樹脂快速固化（D對(duì)），砂粒與樹脂結(jié)合緊密（A對(duì)），但透氣性顯著降低（C錯(cuò)）。選項(xiàng)B正確因樹脂砂強(qiáng)度高導(dǎo)致磨耗加劇?！绢}干8】鑄件熱處理中，退火的主要目的是（）A.提高表面光潔度B.消除內(nèi)應(yīng)力C.增加硬度D.改善切削加工性【參考答案】B【詳細(xì)解析】退火通過再結(jié)晶消除鑄件凝固及冷卻過程中產(chǎn)生的內(nèi)應(yīng)力（B對(duì)）。選項(xiàng)A屬表面處理范疇；選項(xiàng)C需淬火+回火；選項(xiàng)D正火更適用?！绢}干9】鑄鐵件冷熱交替使用時(shí)易產(chǎn)生（）A.氣孔B.縮松C.裂紋D.麻點(diǎn)【參考答案】C【詳細(xì)解析】冷熱交替導(dǎo)致鑄鐵中石墨與基體熱膨脹系數(shù)差異產(chǎn)生應(yīng)力，裂紋多沿石墨分布方向延伸（C對(duì)）。選項(xiàng)A為鑄造缺陷；選項(xiàng)B為凝固缺陷；選項(xiàng)D屬表面缺陷?！绢}干10】鋁合金鑄件熱處理時(shí)，自然時(shí)效的典型溫度范圍是（）A.150-200℃B.200-300℃C.300-400℃D.400-500℃【參考答案】A【詳細(xì)解析】鋁合金自然時(shí)效在150-200℃進(jìn)行，利用室溫氧化析出強(qiáng)化相。選項(xiàng)B以上溫度需人工時(shí)效；選項(xiàng)C和D屬過熱風(fēng)險(xiǎn)范圍?！绢}干11】砂型鑄造中，判斷砂芯是否需要涂料的主要依據(jù)是（）A.鑄件表面光潔度要求B.金屬液溫度C.砂芯尺寸穩(wěn)定性D.砂芯烘干時(shí)間【參考答案】A【詳細(xì)解析】涂料主要功能是控制鑄件表面質(zhì)量（A對(duì)）。選項(xiàng)B影響澆注時(shí)間；選項(xiàng)C屬工藝設(shè)計(jì)；選項(xiàng)D與涂料無關(guān)。【題干12】球墨鑄鐵QT500-7的“QT”代表（）A.球墨鑄鐵B.合金工具鋼C.球狀石墨鑄鐵D.灰鑄鐵【參考答案】C【詳細(xì)解析】QT為球墨鑄鐵（Q-球狀石墨，T-鐵）的代號(hào)。選項(xiàng)A表述不準(zhǔn)確；選項(xiàng)B屬鋼類；選項(xiàng)D為灰鑄鐵代號(hào)（HT）?！绢}干13】鑄造工藝圖中，模數(shù)（Mod）的物理意義是（）A.模型最大尺寸B.分型面至頂面的距離C.鑄件壁厚與模數(shù)之比D.模型與砂型間隙【參考答案】C【詳細(xì)解析】模數(shù)=壁厚/模數(shù)系數(shù)，用于確定鑄件壁厚與模型尺寸比例（C對(duì)）。選項(xiàng)A為模型總尺寸；選項(xiàng)B屬分型距；選項(xiàng)D為鑄型間隙（模數(shù)系數(shù)）?！绢}干14】鑄造缺陷中，夾渣產(chǎn)生的主要原因是（）A.液態(tài)金屬過熱B.模型表面有油污C.氣體未完全逸出D.澆注系統(tǒng)設(shè)計(jì)不當(dāng)【參考答案】B【詳細(xì)解析】油污（B對(duì)）與金屬液反應(yīng)生成夾渣物。選項(xiàng)A導(dǎo)致氧化夾渣；選項(xiàng)C屬氣孔成因；選項(xiàng)D屬設(shè)計(jì)缺陷但非直接原因?！绢}干15】鑄鋼件淬火后，為消除應(yīng)力需進(jìn)行（）A.正火B(yǎng).退火C.回火D.去應(yīng)力退火【參考答案】D【詳細(xì)解析】淬火后殘余應(yīng)力通過去應(yīng)力退火（150-200℃）消除（D對(duì)）。選項(xiàng)A正火用于細(xì)化組織；選項(xiàng)B退火徹底降低硬度；選項(xiàng)C回火調(diào)整力學(xué)性能?！绢}干16】砂型鑄造中，使用酯固化型砂的主要優(yōu)勢(shì)是（）A.粘結(jié)強(qiáng)度高B.透氣性好C.固化時(shí)間可控D.成本低廉【參考答案】C【詳細(xì)解析】酯固化型砂通過調(diào)節(jié)催化劑比例可精確控制固化時(shí)間（C對(duì)）。選項(xiàng)A屬呋喃樹脂砂優(yōu)勢(shì)；選項(xiàng)B透氣性與樹脂類型相關(guān)；選項(xiàng)D為水玻璃砂特點(diǎn)?！绢}干17】鑄鐵件白口傾向高的原因是（）A.碳當(dāng)量低B.合金元素含量高C.孕育處理不足D.冷卻速度慢【參考答案】C【詳細(xì)解析】孕育處理不足（C對(duì)）導(dǎo)致石墨晶核不足，促進(jìn)共晶白口形成。選項(xiàng)A碳當(dāng)量低易石墨化；選項(xiàng)B合金元素可能抑制白口；選項(xiàng)D冷卻慢利于石墨化。【題干18】鑄造工藝中，判斷鑄件是否需要芯撐的主要依據(jù)是（）A.鑄件壁厚小于3mmB.芯砂強(qiáng)度不足C.芯體尺寸穩(wěn)定性差D.鑄件結(jié)構(gòu)復(fù)雜【參考答案】A【詳細(xì)解析】薄壁件（A對(duì)）易變形需芯撐支撐。選項(xiàng)B屬工藝缺陷；選項(xiàng)C屬設(shè)計(jì)問題；選項(xiàng)D復(fù)雜結(jié)構(gòu)需分型面優(yōu)化。【題干19】鋁合金鑄件時(shí)效處理時(shí)，人工時(shí)效與自然時(shí)效的主要區(qū)別是（）A.溫度不同B.時(shí)間不同C.強(qiáng)化效果不同D.晶粒大小不同【參考答案】B【詳細(xì)解析】人工時(shí)效在150-200℃進(jìn)行數(shù)小時(shí)（B對(duì)），自然時(shí)效在室溫下需數(shù)周。選項(xiàng)A溫度范圍相同；選項(xiàng)C效果相近；選項(xiàng)D晶粒度無顯著差異?！绢}干20】鑄造缺陷中，熱裂多發(fā)生在（）A.鑄件最后凝固區(qū)域B.鑄件厚大斷面C.鑄件薄壁處D.鑄件排氣孔附近【參考答案】A【詳細(xì)解析】熱裂由凝固收縮應(yīng)力引起，集中在最后凝固區(qū)域（A對(duì)）。選項(xiàng)B厚大斷面先凝固；選項(xiàng)C薄壁處易產(chǎn)生縮松；選項(xiàng)D排氣孔處無應(yīng)力集中。2025年事業(yè)單位工勤技能-北京-北京鑄造工一級(jí)（高級(jí)技師）歷年參考題庫含答案解析(篇4)【題干1】砂型鑄造中，適用于制造灰鑄鐵件的型砂應(yīng)優(yōu)先選用哪種材料？【選項(xiàng)】A.濕砂B.水玻璃砂C.樹脂砂D.砂芯砂【參考答案】A【詳細(xì)解析】濕砂型適用于灰鑄鐵件，因其透氣性好，能有效排出型腔內(nèi)的氣體。水玻璃砂透氣性差易產(chǎn)生氣孔，樹脂砂冷卻快易產(chǎn)生白口，砂芯砂用于制造砂芯而非型砂?！绢}干2】鑄造缺陷中，氣孔形成的根本原因是？【選項(xiàng)】A.模具設(shè)計(jì)不合理B.澆注系統(tǒng)排氣不良C.材料熔煉不充分D.冷卻速度過慢【參考答案】B【詳細(xì)解析】氣孔的直接原因是澆注時(shí)氣體無法及時(shí)排出，導(dǎo)致氣體滯留。模具設(shè)計(jì)不合理可能間接影響排氣，但非根本原因；材料熔煉不充分可能引入雜質(zhì)，冷卻速度過慢易產(chǎn)生縮孔而非氣孔?！绢}干3】球墨鑄鐵的孕育處理通常在什么溫度區(qū)間進(jìn)行？【選項(xiàng)】A.800-900℃B.950-1000℃C.700-750℃D.600-650℃【參考答案】B【詳細(xì)解析】孕育處理需在鐵液接近熔點(diǎn)時(shí)進(jìn)行，950-1000℃時(shí)碳硅反應(yīng)充分，促進(jìn)石墨球化。700-750℃為共晶溫度，易形成萊氏體；600-650℃鐵液已凝固?！绢}干4】鑄件熱處理中，退火的主要目的是？【選項(xiàng)】A.提高表面光潔度B.改善切削加工性C.消除內(nèi)應(yīng)力D.增加耐磨性【參考答案】C【詳細(xì)解析】退火通過緩慢冷卻降低內(nèi)應(yīng)力，恢復(fù)材料塑性。改善切削加工性需正火或調(diào)質(zhì)處理，表面光潔度需通過拋光或電鍍，耐磨性需表面硬化處理。【題干5】鑄鐵件平衡組織中的石墨形態(tài)是？【選項(xiàng)】A.球狀石墨B.疏松石墨C.蠕蟲狀石墨D.細(xì)片狀石墨【參考答案】A【詳細(xì)解析】球墨鑄鐵的平衡組織為球狀石墨，蠕蟲狀石墨為過共晶成分，細(xì)片狀石墨常見于灰鑄鐵，疏松石墨為鑄造缺陷。【題干6】砂型鑄造中，型砂配比中黏土的適宜含量范圍是？【選項(xiàng)】A.5%-10%B.10%-15%C.15%-20%D.20%-25%【參考答案】B【詳細(xì)解析】黏土含量10%-15%時(shí)，型砂強(qiáng)度和透氣性平衡，過高易導(dǎo)致透氣性差和鑄件氣孔，過低則強(qiáng)度不足?！绢}干7】鑄造鋁合金時(shí)，熔煉溫度過高會(huì)導(dǎo)致什么缺陷？【選項(xiàng)】A.晶粒粗大B.氣孔增多C.縮松嚴(yán)重D.表面氧化【參考答案】C【詳細(xì)解析】鋁合金熔點(diǎn)范圍窄（約600-660℃），溫度過高會(huì)加速氧化和合金元素?fù)]發(fā)，導(dǎo)致縮松和夾雜物增多，晶粒粗大是溫度過高的次生缺陷?！绢}干8】鑄鋼件熱處理中，正火的主要作用是？【選項(xiàng)】A.消除內(nèi)應(yīng)力B.增強(qiáng)韌性C.細(xì)化晶粒D.提高表面硬度【參考答案】C【詳細(xì)解析】正火通過完全重結(jié)晶細(xì)化晶粒，改善切削加工性，消除內(nèi)應(yīng)力是退火作用，提高表面硬度需表面淬火?！绢}干9】砂型鑄造中，為防止鑄件粘砂，應(yīng)在型砂中加入什么材料？【選項(xiàng)】A.云母粉B.石墨粉C.滾珠D.水玻璃【參考答案】B【詳細(xì)解析】石墨粉可降低型砂表面黏附性，水玻璃砂用于鑄鐵件防粘，云母粉用于耐高溫鑄型，滾珠用于金屬型。【題干10】球墨鑄鐵的孕育處理不足會(huì)導(dǎo)致什么缺陷？【選項(xiàng)】A.萊氏體殘留B.石墨片狀C.晶粒粗大D.氣孔過多【參考答案】B【詳細(xì)解析】孕育不足會(huì)導(dǎo)致石墨形核能力差，形成片狀石墨，降低強(qiáng)度和韌性；萊氏體殘留是過共晶缺陷，晶粒粗大是熔煉溫度過高導(dǎo)致?！绢}干11】鑄造鋁合金時(shí)，常用的變質(zhì)處理劑是？【選項(xiàng)】A.硅鐵B.鋁硅合金C.氟化鈉D.酚醛樹脂【參考答案】B【詳細(xì)解析】鋁硅合金（Al-Si）用于變質(zhì)處理，促進(jìn)α相形成，細(xì)化晶粒；硅鐵用于脫氧，氟化鈉用于熔劑，酚醛樹脂用于砂型粘結(jié)?！绢}干12】鑄件熱處理中，淬火后的回火溫度選擇主要依據(jù)什么？【選項(xiàng)】A.鑄件壁厚B.材料含碳量C.使用要求D.熱處理設(shè)備【參考答案】A【詳細(xì)解析】壁厚影響冷卻速度，決定殘余應(yīng)力大小和回火溫度。含碳量決定硬度要求，使用要求決定回火硬度，設(shè)備影響工藝可行性?！绢}干13】砂型鑄造中，澆注系統(tǒng)的設(shè)計(jì)原則不包括？【選項(xiàng)】A.保證充型能力B.防止鑄件變形C.減少熔煉時(shí)間D.排氣功能完善【參考答案】C【詳細(xì)解析】澆注系統(tǒng)需保證充型能力、排氣功能和防止變形，減少熔煉時(shí)間屬于熔煉工藝優(yōu)化，與澆注系統(tǒng)無直接關(guān)聯(lián)。【題干14】鑄鐵件熱處理中，退火與正火的區(qū)別主要在于？【選項(xiàng)】A.保溫時(shí)間B.冷卻速度C.熱處理設(shè)備D.金相組織轉(zhuǎn)變【參考答案】B【詳細(xì)解析】退火緩慢冷卻（爐冷），正火快速冷卻（空冷），導(dǎo)致退火得到均勻組織，正火細(xì)化晶粒并改善切削性。【題干15】鑄造缺陷中，縮孔的形成與什么因素直接相關(guān)？【選項(xiàng)】A.模具精度B.澆注溫度C.冷卻速度D.材料純凈度【參考答案】B【詳細(xì)解析】縮孔是液態(tài)金屬冷卻收縮時(shí)體積不均勻?qū)е碌?，澆注溫度高?huì)延長(zhǎng)凝固時(shí)間，加劇收縮不均；模具精度影響鑄型尺寸，材料純凈度影響夾雜物分布。【題干16】砂型鑄造中，為提高鑄件強(qiáng)度，應(yīng)如何控制型砂強(qiáng)度？【選項(xiàng)】A.增加黏土含量B.提高砂粒硬度C.降低水分含量D.使用樹脂砂【參考答案】C【詳細(xì)解析】型砂強(qiáng)度與黏土含量、水分含量和砂粒硬度相關(guān)，降低水分可提高型砂強(qiáng)度和透氣性；樹脂砂強(qiáng)度高但透氣性差，需配合其他工藝。【題干17】球墨鑄鐵的孕育處理過早會(huì)導(dǎo)致什么缺陷？【選項(xiàng)】A.石墨球化不良B.晶粒粗大C.表面氧化D.氣孔增多【參考答案】A【詳細(xì)解析】孕育過早（鐵液溫度低于950℃）會(huì)導(dǎo)致孕育劑未充分反應(yīng)，石墨形核率低，球化不良；晶粒粗大是溫度過高的結(jié)果，表面氧化是熔煉過程問題?！绢}干18】鑄造鋁合金時(shí)，為防止熱裂，需加入什么元素？【選項(xiàng)】A.鉻B.鎂C.錫D.鈦【參考答案】B【詳細(xì)解析】鎂可提高鋁合金的延展性，預(yù)防熱裂；鉻用于耐腐蝕合金，錫用于易切削鑄鐵，鈦用于高溫合金?！绢}干19】鑄鋼件熱處理中，調(diào)質(zhì)處理的主要目的是？【選項(xiàng)】A.提高表面硬度B.增強(qiáng)耐磨性C.綜合強(qiáng)韌性D.改善切削加工性【參考答案】C【詳細(xì)解析】調(diào)質(zhì)（淬火+高溫回火）得到回火索氏體，綜合強(qiáng)度和韌性；表面硬度需表面淬火，切削加工性需正火或退火?！绢}干20】砂型鑄造中，為提高鑄件致密性，應(yīng)如何控制澆注系統(tǒng)？【選項(xiàng)】A.增大內(nèi)澆口截面積B.優(yōu)化排氣道設(shè)計(jì)C.提高澆注溫度D.增加冒口高度【參考答案】B【詳細(xì)解析】排氣道設(shè)計(jì)不良會(huì)導(dǎo)致氣體滯留形成氣孔，優(yōu)化排氣道可減少氣孔，增大內(nèi)澆口截面積影響充型速度，澆注溫度高會(huì)加劇收縮缺陷，冒口高度影響補(bǔ)縮而非排氣。2025年事業(yè)單位工勤技能-北京-北京鑄造工一級(jí)（高級(jí)技師）歷年參考題庫含答案解析(篇5)【題干1】鑄鐵中硅含量增加會(huì)顯著提高其灰鑄鐵的流動(dòng)性，這是由于硅元素在鐵液中()【選項(xiàng)】A.形成碳化物B.促進(jìn)石墨化C.提高熔點(diǎn)D.增強(qiáng)氧化性【參考答案】B【詳細(xì)解析】硅元素在鐵液中能顯著促進(jìn)石墨化過程，降低碳的共晶點(diǎn)溫度，使石墨析出量增加，從而提高灰鑄鐵的流動(dòng)性。此知識(shí)點(diǎn)為鑄造材料熱處理核心考點(diǎn)，需掌握合金元素對(duì)鑄鐵性能的影響規(guī)律。【題干2】砂型鑄造中，型砂配砂時(shí)加入的黏結(jié)劑主要作用是()【選項(xiàng)】A.提高型砂透氣性B.增強(qiáng)型砂強(qiáng)度C.改善砂粒流動(dòng)性D.降低砂型收縮率【參考答案】B【詳細(xì)解析】黏結(jié)劑（如樹脂或粘土）的核心作用是增強(qiáng)型砂顆粒間的粘結(jié)力，確保砂型在起模后保持結(jié)構(gòu)完整。此題型常與型砂配比相關(guān)考題結(jié)合出現(xiàn)，需注意區(qū)分不同砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂砂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